Andrew, thanks for the info regarding tongue weight on Euro trailers. In Europe, it is extremely common to see subcompact cars. I was over in Europe about 2 months ago. While riding a bus through town, I started counting hitches on cars parked on the street... and about 1 out of 4 cars had hitches on them. Many of these cars are sub-100 hp cars. Nobody drives pickup trucks over there. Mini vans and SUVs aren't very common, and tend to be smaller than ours. The hitches over there are "swan neck" hitches, where there is just a ball -- no receiver. So, people with hitches are using them to tow, not to haul bicycles and such. I saw many small cars towing little trailers... about 4'x6' galvanized. I also saw some relatively large caravans (travel trailers) being towed by small cars and SUVs. I was really curious about the weight of them... they didn't look light.
My point, if I have one, is that towing with small cars is very common in many European countries... but not so common here in N.A. Car companies know that to sell their cars over there, they must be rated to tow a decent amount. Like I said before, over here they want to sell trucks to people who want to tow small trailers, and they are worried about lawsuits due to damage and/or injuries from towing mishaps.
In my store, I used to sell a sugar syrup in a can that is made in the UK. A customer of mine had his house nearly destroyed by a fire, and the only thing they could find in his basement (where the fire started) was an empty can of that sugar and a container of cleaning wipes. His insurance company sued Clorox, the british company, and my store for damages. Believe it or not, they ended up winning. Why? Because it would have cost all of us more in expert witnesses and lawyers to prove that an empty can of sugar and a box of cleaning wipes can't cause a fire. The British company promptly left the US market.
That shows you the kind of idiotic behavior that goes on in and out of our courthouses. I don't blame car companies for wanting to relieve themselves of any kind of legal responsibility.