In high opl when judge can interrupt a game?

A judge can interrupt a match at high OPL only in three situations: they believe a rules or policy violation has occurred, a player requests assistance, or they observe Unsporting Conduct (Rule 701.1.d).

Otherwise, judges are told not to intervene — they should not stop errors from occurring, only deal with errors that have already happened (Rule 701.1.c). Players can also pause at any time to flag a floor judge (Rule 412.1), and deck checks at high OPL are an allowed interruption (Rule 411). One important limit: a judge who discovers a previous ruling was wrong should wait until the current match is over rather than interrupt the ongoing game (FAQ 5409).