I feel there may be a difference between what is done at a play party and what is done between a couple in their own dungeon. PArtly this is due to laws on public displays of lewdity. I suspect you can get away with whipping a naked woman on stage and call it 'artistic' in a performance art sort of way but showing erect male genetalia or actual intercourse is generally seen as pornography and often illegal... One thing to ask - do they talk about the close bond between the couple on stage or is it just a Dom and 'some sub they got to do the demo'?