When you rent a trailer from Cowboy Trailers & Equipment, you may have two insurance paths: use your own auto insurance, or choose Supplemental Liability Insurance during checkout. Supplemental Liability Insurance, often called SLI, is optional. It is not required to rent a trailer, and MBA Insurance’s current SLI materials also state that purchase of this insurance is not required to rent a vehicle.
For many renters, their personal auto policy may already extend liability coverage while towing a trailer behind an insured vehicle. Insurer guidance commonly explains that the towing vehicle’s liability coverage can apply to damage or injuries you cause to others while the trailer is properly attached and being towed, but that does not automatically mean the trailer itself or the cargo inside it is covered for physical damage. Because policies differ, the safest step is to verify your exact coverage with your insurer before pickup.
What is Supplemental Liability Insurance?
Supplemental Liability Insurance is excess third-party liability coverage. MBA describes its SLI as insurance that protects you and authorized drivers against third-party automobile claims for bodily injury and property damage caused during authorized use of the rental vehicle. In other words, it is designed to help with claims from other people if you are legally responsible for an accident.
MBA’s SLI terms also say this coverage is excess or last-payor coverage. That means it generally applies after other valid and collectible insurance has been used first, including applicable personal auto insurance and other underlying coverage. MBA’s published SLI terms for private passenger vehicles currently reference a maximum total aggregate limit of up to $500,000, with an internal bodily injury limit of $100,000 per person, and property damage up to $50,000, subject to the policy terms and reductions described in the contract.
Is SLI required to rent a trailer?
No. At Cowboy Trailers & Equipment, SLI is an optional add-on, not a requirement. MBA’s own SLI page states that purchase of the insurance is not required in order to rent a vehicle, and it also warns that the coverage may duplicate protection a renter already has under a personal insurance policy or another source of coverage.
Why should renters check with their insurance company first?
Because “my insurance covers trailers” can mean different things depending on the policy. Many policies may extend liability while towing, but exclusions, limits, and conditions still matter. Some insurers specifically tell customers to confirm exact details, coverages, and exclusions with their agent or carrier. That is the best way to know whether your liability extends to a rented trailer, whether only third-party liability is covered, and whether there are any gaps you should fill with optional protection.
Before pickup, ask your insurance company these questions:
- Does my liability coverage extend while towing a rented trailer?
- Are there any exclusions for the trailer type I am renting?
- Am I covered only for damage I cause to others, or is there any coverage for the trailer itself?
- Are there any driver, use, territory, or business-use restrictions?
- What deductible would apply if I make a claim under my own policy?
Those questions help the renter make a real coverage decision instead of guessing.
What are the advantages of buying SLI?
The biggest advantage is added liability protection above underlying coverage. If your policy limits are low, if you are unsure whether your policy fully extends while towing, or if you simply want another layer of third-party liability protection for the rental period, SLI can provide extra peace of mind. It can also make the decision simpler for renters who want a temporary, rental-specific option at checkout instead of relying only on assumptions about their personal policy.
Another advantage is clarity around the rental transaction itself. MBA’s trailer renter materials explain that, for eligible rentals, renters may purchase trailer liability-related coverage through the operator’s program, and SLI can be purchased separately as an optional coverage.
What are the advantages of not buying SLI?
The main advantage is simple: you may save money if your own insurance already gives you the protection you need. MBA specifically notes that optional insurance products may duplicate coverage already provided by your personal insurance or other sources of coverage. If you have already confirmed strong liability limits with your insurer and you are comfortable with those limits, you may decide not to add SLI.
What SLI does not replace
SLI is not the same thing as physical-damage protection for the trailer. MBA’s SLI terms exclude property damage to the rental vehicle, and other insurer guidance commonly explains that the towing vehicle’s liability coverage may protect against damage you cause to others, but not necessarily damage to the trailer itself or its contents. SLI also has important exclusions, including unauthorized drivers, illegal use, intoxication, certain off-road use, and travel into Mexico.
That means renters should not assume SLI covers every possible loss. It is focused on third-party liability, not “everything that could go wrong.” Always read the contract you receive at pickup and make sure all authorized drivers and permitted uses are correct.
Will I have to pay a deductible if there is an accident?
That depends on which policy responds and what kind of claim it is. The Texas Department of Insurance explains that deductibles commonly apply to collision, comprehensive, and uninsured/underinsured motorist claims. A deductible is the part of a covered claim you pay out of pocket before insurance pays the rest.
For renters using their own auto insurance, a deductible may apply if they make a claim under their own collision or other first-party coverage. But liability claims do not work the same way as collision/comprehensive claims, and out-of-pocket responsibility can differ depending on who is at fault and what coverage is being used. MBA’s SLI page describes SLI as excess third-party liability coverage and does not present it as physical-damage coverage for the trailer. The exact contract and your own policy terms should control.
Important things renters should know before towing
SLI applies only to authorized drivers and only during authorized use under the rental agreement. MBA’s published terms also state that coverage territory includes the United States, Puerto Rico, and Canada, but not Mexico. The terms also limit or exclude coverage for intoxication, illegal use, racing, off-road use, towing other autos, damage to the rental vehicle, and property in the renter’s care, custody, or control.
For Texas renters, state minimum auto liability requirements are currently 30/60/25, meaning $30,000 for injuries per person, $60,000 per accident, and $25,000 for property damage. Some renters choose optional protection because they want an additional layer above their underlying policy limits during the rental period.
Our recommendation
If you already know your personal auto policy extends liability while towing a rented trailer, and you are comfortable with your limits, you may decide to decline SLI. If you are unsure, carry only minimum limits, or want added third-party liability protection for the rental period, selecting Supplemental Liability Insurance may be the better choice. In either case, the smartest move is to call your insurer before pickup and confirm exactly what is and is not covered.
At Cowboy Trailers & Equipment, when SLI is selected during checkout, we purchase it through MBA Insurance and provide the contract to the renter on pickup day so the renter can review the coverage documents with the rental paperwork.
Frequently Asked Questions
Does my car insurance cover a rented trailer?
Often, your vehicle’s liability coverage may extend while towing a trailer, but that does not automatically mean the trailer itself or its contents are covered for physical damage. You should confirm exact limits, exclusions, and deductible details with your insurer.
Is Supplemental Liability Insurance mandatory?
No. It is optional. MBA’s SLI materials say purchase of the insurance is not required in order to rent a vehicle.
What does SLI usually help cover?
SLI is designed for third-party bodily injury and property damage claims caused during authorized use by an authorized driver. It is excess coverage above other valid and collectible insurance.
Does SLI cover damage to the rental trailer?
Not as described in MBA’s SLI terms. Their SLI exclusions include property damage to the rental vehicle.
Does SLI have a deductible?
The contract should always be reviewed for exact terms. In general, deductibles are most commonly associated with first-party coverages like collision and comprehensive, while MBA’s SLI is described as excess third-party liability coverage.
Can anyone driving my tow vehicle be covered?
No. Coverage is tied to the rental agreement and authorized drivers. An unauthorized driver can void coverage.
Call to Action
Questions before you book?
Contact Cowboy Trailers & Equipment and we’ll explain how the optional Supplemental Liability Insurance checkout process works. We can help you understand the rental paperwork, but you should always confirm your personal coverage directly with your insurance company before towing.