This would be the thing to come back to bite you if you're ever in an accident and a smart lawyer knows about this.
SAE has set the standards for towing and most auto manufacturers have accepted it and are labeling their vehicles as compliant.
The standard for frontal area maximum is set by vehicle class as I understand it.
I've been trying to get a copy of the SAE J2807 which is the standards by which towing capabilities are measured with, but have been unsuccessful at this time.
This sets the maximum frontal area for towing with full size pickups at 60 sq ft. for trailers and full size suvs at 60 sq ft for trailers. All full size SUVS or Pickups apparently have the same standard. Mid size SUV's seem to be set around 32 sq ft. which means TT's or HTT's will be out of the question.

The vast majority of us never have an accident while towing the trailer, but I can see someone with a Chevy Traverse or Ford Explorer (any other mid size SUV) towing a small HTT or TT  being involved in an accident that was not their fault. All an opponents lawyer will have to do is see that your are exceeding the FAL (frontal area limit) for the vehicle class and he will try make you responsible or partially responsible for the accident. He doesn't have to know any weights that may have been in excess to prove (very difficult) that you were overloaded. All he has to do, is get a copy of the vehicle class and trailer type SAE standard and voila, the SAE has made his case.

With everything on Lexus-Nexus or the like for lawyers, if the first case hasn't happened, it will.

Besides that, I and my family be more secure in knowing that a particular class of vehicle has not only been certified (maximums)  to tow a trailer by the SAE, but also by the automaker. They have taken some liability when they set the standard.