There is not, but there's a chance that the game will be cut short if it takes too long. I think under 30 minutes is somewhat safe, but after that it becomes iffy
It depends on the moment, if everyone watching is enjoying it and I am not having an awful time, then maybe I'll be able to finish the game. But if it drags on, and we're getting bored (and people are getting annoying I am playing 1 game for too long) well then I'll probably cut it short.
