In my humble opinion, the universal stop sign should NOT be the first attempt to address the coach. I think there has to be a progression.
Some officials are able to manage coaches with the many "tools" of preventative officiating such as dead ball diplomacy, etc. I have "T'd" very few coaches.
Often times it only takes a simple reminder, early in the game, to set my level of expected behavior of the coach: "Coach, I view this gym as a classroom and your conduct should be that of a teacher."
This has worked well with most coaches. The one who did not "get it" got the "T" (I skipped A thru S
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