Well, at least one major adult cam site banned streaming games a few years back due to copyright concerns. Not sure about other sites but I suspect they'd end up having to do the same thing if it caught on there; the plausible deniability of being on a games streaming site is important if you want to be able to stream games, since it's at best a bit of a copyright grey area and developers don't have the same incentive to permit adult streamers as they do plain game streamers.