About time!!!!
Is this at every point of the match, or only after a certain amount of time has elapsed?
That is the full rule for that aspect, so it appears to apply at all times.
Edit to correct some errors...
I just noticed the following... There is a foul cancellation rule, so both players cannot be negative. Also, I see this:
Ball Count of -5 Loss of Game
Any ball count score that reaches negative five (-5) is loss of game.
There is also this:
4 Hour Match Limit
The player that is leading in the game and ball count wins the match. If both players are tied in the game and ball count, the next player to take the score lead (games plus ball count) wins the match. (This score lead can be determined by pocketing a ball or a foul shot)
I can imagine some five-minute shots, depending on the score. I pity the player who is behind 2-1 with half an hour left. There will be situations where blasting the balls with no particular shot in mind is the right play.
