A couple of thoughts....

In a pro session I've always depended on the skill of the Domme to prevent an "accident" during tease and denial. I've never had it happen but if one was to occur it would depend on when in the session it happened. At the 30 minute mark of a two hour session I would want to continue even if that required a break or a period of CNC play ( I would have discussed this before the session). If it was near the end of our time I would consider the session done but be a little annoyed at the Domme over the situation.

Playing privately I've always negotiated that the Domee is in charge (subject to agreed parameters and limits). In that case I would be surprised if a fairly severe punishment didn't happen followed by being left in bondage until recovered and then having play resume.

I've been in private, non pro sessions where the Domme has purposely pushed me over the edge after giving me strict orders not to lose control as an "excuse" to inflict penalties. Not at all enjoyable at the time but a very hot memory to look back on. grin