idk.. this is kinda murky, especially with porn. i'm not advocating going haywire
but i am pretty dam* sure that most of these tubes started illegally. almost all of the porn companies are owned by only a few. i believe xvids is owned by one media group (whose owner wants to remain anonymous) and pornhub is owned by another media group, but from there i think most porn companies fall under those two roofs.
beyond that, have you ever worked as an affiliate at some of those sites? they give you promo videos that you can upload. i think most porn companies resigned to the fact that they cant control who uploads and where so they try to make money when they can. now, if you upload a brazzers vid and try to send them to twisty's then yea, that's prob not gonna be good..
but also, im pretty sure the problem is with the host. unless xvids or something turns around and then sues you for recovering the damages
idk how that works, but good bet majority of the time they'll just close your account/ remove the vid(s)