I think something that needs to be taken into consideration with everything is consent. One special interest I've seen a lot on this list is rape, but there is such thing as consensual non-consent or a literal rape special interest. The individuals participating in this aren't interested in actually raping anyone but where is the harm in their playing out their fantasies as consenting adults? That's where I've always stood on the special interest subject. Whatever anyone does is fine with me as long as they don't actually act upon anything dangerous or nonconsensual.