One that I like to do is if I have the rule memorized. I'll just quote the reference.
I had coach upset at me one time because his player A1 inbounding from the side line put the ball over the line and the defender B1 hit it out of A1's hand without touching him. Then dribbled in for the score.
Running by I just said 9-2-11. He questioned me and I said Rule 9 section 2 article 11 go look it up.
This usually quiets them down because their thinking, if I can quote the rule by number, I probably know what I'm talking about and he'd better go look it up.
It also makes you more credible the next you see the coach.
P.S. No!!!! I don't have all the rules memorized. Still working on that one.