We generally have an unspoken rule that we look for lost arrows at a tournament no more than 4-5 minutes per target. Another unspoken rule is that the guy who lost the arrow should be the one to speak up and say, "Let's move on, folks, I'll come back and look for it after the tournament," or some such. So far, everyone seems to be doing that, because I don't remember being held up for lost arrows for very long. If you still have to wait at the next target after you looked for lost arrows, then obviously you weren't holding anyone up by looking.
There always seems to be a bottleneck somewhere during a tournament, where 3-4 groups are backed up. This seems to be a bigger problem at mixed compound and trad tournaments than trad only tournaments. It seems to be a rule at tournaments where compounders shoot that only one person can shoot at a time, and after every shot each person in the group has to look at the target with their binoculars and give some sort of commentary on the shot.
OTOH, I think if we trad shooters would take a little more time between shots, more of our arrows would go in the target and we would spend less time looking for lost arrows.