As a non-legal expert I'll offer this; I make a steel bar capable of handling a 14K load off the end of a trailer hitch. If tested later it can be proven that the bar does handle 14K load, I'm off the legal hook so to speak. If the steel bar applies enough load to tear the hitch off my truck the first question will be what is the manufactures rating. Was it designed to handle a two foot extension
These and other question can not be answered by anyone hear. Also civil suites are done in private and we as individuals will not know the outcome,
All I can say is wow! Thousands of people all over this country have used these extensions for 50 years now, they have been proven safe and I think you are going overboard in your assessment, of the technology. If they were bad technology, with the amount of campers in this county, we would have heard about it by now.
So now when it goes back to the original poster, either you use an extension bar and get it set up correctly, get a smaller camper, or take a second vehicle with you to tow your boat.
And really you don't know if the question can be answered by someone posting here. Really when it comes down to it, it is up to the guy that bought a camper that creates a situation for him towing his boat.
Just to add, where I live, civil suits are not done in private, every week, we have listings in the news of the civil suits file that week, just finished watching the weekly report on it. Nothing filed in a court of law is private, unless a judge orders it to be private. When it comes to products suits, it is never private if the public at large could be affected.