How common are parks with "cheater" 50amp service?

I'm sure it would be a violation of code. NOW.

But I've heard that the code used to pay very little attention to RVs and RV parks. Does anyone here know WHEN RVs started coming with 50 amp service instead of 30 amp?

Cause I think it's possible that old campgrounds might have been wired by the camp 'handyman' back when they had to upgrade their pedestal. And if the incoming power from the electric company wasn't that great, they might have taken the easy - and cheap - way out.