USA rules....sub rule

[FMadera]

Originally Posted by Antonio.King

Allow one of them (should they decide quickly which of the two they want to actually use), and deny the other and issue an improper request.

In a perfect world, you're already telling the coaches they've used the 9th, 10th, and 11th, so when two people come up, you let them know they need to choose which one (quickly) and allow that sub. I wouldn't issue an improper request because the request for sub was legal (since they had a sub remaining), and we're not really denying anything, just making them choose (like if someone crosses the attack line and we blow the whistle).

Now, if they hem and haw over which sub they want, etc, you can deny both of them and issue a delay warning, but if you've done your due diligence ahead of time, you can just say "only one of you" and they'll get the hint without issues.