This is not a new problem. Many years ago, I was interested in purchasing a new TT. I had a Chevy 1500 TV. At the time, there was no internet to do research and no forum to ask for advice. I had to go by what the salesman told me. He talked me into this nice little 30' FW! I don't remember the weight of the FW, but when I hooked up, the rear end of the truck squatted a good 4-5". My headlights looked like they were aimed into the heavens. I towed it a few times, and lost the transmission at 35,000 miles. Once the transmission was fixed, I immediately traded the truck in for a 2500 version and got many happy miles with it.
Since then, I always try to buy less trailer than my TV is capable of handling. With the internet and forums, it seems hard to understand why folks don't do their research before making a purchase.