i think that if you value the emotional experience of vulnerability in spanking, then it is essential that the top assume more responsibility for the safety of the bottom.
that said, it is the bottom's responsibility to choose who she plays with carefully, and watch the kinds of situations she gets into. i haven't ever played in a group situation or with strangers really. but if i were somehow hurt after choosing to do that, i wouldn't feel like i could blame the spanker. i mean, i probably wouldn't want to lay eyes on him again. but i would feel that it was my own fault for incorrectly assessing my surroundings or letting my guard down when it wasn't safe to do so.
in my relationship situation, the people who spank me really want me to let down my guard and let go of control and responsibility, so it's essential that i do that and trust them to handle me carefully. they definitely assume that responsibility themselves; i'd never have to push it on them. and because there's three of them, they sometimes check each other. as in, 'careful with that implement, she's sensitive with that' or 'i think that's enough for her for now' or even 'you could probably keep going.' that whole thing makes me feel doubly safe.
