It's been my experience that even at state playoffs the rules aren't always enforced. Usually someone will complain about something and then something might happen, but in the end it's nothing more than the loser complaining about losing due to something that shouldn't have happened. Nice guys finish last. Next time, make a big deal out of it when they come back and get them annoyed so they mess up in the tiebreak.
Honestly, if you've split sets and instead of a 3rd set it's a 10 point tiebreak, that should be played without any delay. Whatever momentum the second set winner had will wash away if there's an excessive break there. The 2nd set winner usually knows this and that's why they do it.
Had a guy once during Flex Mixed pull this bathroom break move, except that the clouds were rolling in and we knew we'd have maybe 5 minutes to finish that 10 point tiebreak before the rains came. Guess what. Dude took so long the rains started after playing 1 point. We had to walk away and postpone the match to finish another day because of it. Luckily, turns out just down the street at another set of courts we sometimes use it was dry, so we called his partner up and told them to show back up and we'd finish that day. Needless to say, we won the tiebreak since the guy was all frazzled it went down like that. He didn't argue, but he wasn't happy either. Somehow, I know deep down he knew he was just as wrong to pull the bathroom break thing when he knew we were expecting rain any moment. To this day I haven't seen this guy pull that kind of move anymore. I guess he learned his lesson.