Quote Originally Posted by BDSM_Tourguide
I'd venture to guess that, when a submissive plays in front of a huge crowd of people, her limits are more likely, not less likely, to be respected and her safeword heeded if it is used. After all, assault and battery in front of a room full of witnesses is not very smart, now is it?
True-- but actually I'm thinking more of her reactions and comfort. While it's unlikely that anyone will break limit rules during a scene, it's more important for her own peace of mind that she find methods to establish trust first...

...which is pretty much what the rest of your post said to do, and I agree. The best and safest thing to do is to get to know people before doing scenes... if they come across as the wrong sort in conversations, then that's instinct saying NO. If no one knows them, and you don't get to know them, skip 'em and wait until you know them better.