[Adam]

For a shoe lace, I'll delay a throw-in once, but I'm not stopping play.

As for the liability line, I wouldn't reply to the coach on the end of the bench. If he continued, I'd remind the HC that he needs to reign his bench in a bit. As for his sarcastic thank you, not much you should do at that point. If the HC mentions it as a safety issue, I wouldn't say anything either (mainly because play is ongoing here).

I can tell you most varsity (and JV) coaches know better, at least around here. If I stopped a game for a shoe lace, I'd be getting some "coaching" from my assigner the next day most likely.

I would have done it the same way.