My crew has a simple solution to questions from coaches who don't "believe" us on a rule. After the game, if the coach approaches us, my white hat will meet the coach near the locker rooms, hand him a business card, and ask that he email with the question and then we'll get back to him (the coach) with a response with the rule references, etc. We've only had to do this once a year, if even that. This year, we had to pacify a coach who thought that ANY contact with the head was illegal (this was after his quarterback got sacked while crouching down to absorb the blow and the defender was on top of him in such a way his arms were wrapped around the QB's head as they were going down).