Varies. With most of the mistresses I've seen there has been a safeword. However have been exceptions including a switch I played around with a lot around the turn of the century. We pushed each other limits a few times but with an understanding that what goes around comes around.

With Mistress Natalie I normally have a safeword (which I've never used) However we did an unusual bit of public play recently where I put myself at risk of a session which most definitely would NOT have a safeword.

I wrote a review of it you can read here: http://domina.ms/~domroot/thebuzz/ubbthreads.php?ubb=showflat&Number=3510#Post3510