After seeing videos like
this or
that, I believe anything is possible in photoshop. Although these two are rather obviously not real, but I hope you get my point.
If you mean mainly the Slave/Master Area, then I stick to the point I made.
It's a relationship, and it's only the business of the people involved. Usually if people are known, then they will get comments from other people stating that they are known and should be trusted.
I don't think there is a verification needed.
Also, personally I would never go into a D/s relationship without the other people confirming their identity, preferably on voice/cam!