i completely agree with Oz that the answer to this question largely lies in the type of submissive a person is. i'm slave, so there would be absolutely no question. i wouldn't need to pull Master aside and make sure the other person was clean: of course he would be. Master would never endanger me; otherwise i wouldn't be wearing His collar. And if Master didn't tell me beforehand, then i would know that was purposefully done to add an element of surprise, not because He is taking advantage of my service and submission.

i feel this is a pretty basic thing to go over though. i mean, if you have a master or dominant and you aren't sure whether this could happen, then yes you guys have some serious communication catch-up to do. BDSM is all about trust and communication...so it's important to know where the boundaries are, which ones are movable and which ones aren't, and maybe even have an idea of how much and often the movable ones can or will be moved around, and it's important to trust your owner. i mean, if you don't have a clear idea of the limits, and then when things happen if you can't trust in your master 100%, then seriously what's the point in being owned by that person?

But let me just say that were i not owned by Master, and i was just with someone in a relationship and they pulled that kind of shit, i would kick them out of the house without batting an eyelash.