When playing a game of Quidditch does the game ever completely stop?
The book mentions penalties and medical aid. But if there was a break in play in these cases then whenever the other team's Seeker was near the snitch you would simply assault the nearest player, forcing the Seeker to break his chase and lose the snitch.
Per "Quidditch through the Ages"
The Captain of a team may call for ‘time out’ by signalling to the referee. This is the only time players’ feet are allowed to touch the ground during a match. Time out may be extended to a two-hour period if a game has lasted more than twelve hours. Failure to return to the pitch after two hours leads to the team’s disqualification.
Although it's not explicitly stated, most games have a "play on" rule that allows for play to continue for a short period after a foul has occurred, in order to prevent a team from intentionally causing a foul in order to gain a deliberate advantage.
