Yea that's exactly what I'm trying to avoid. I hate how it sometimes disrupts the flow of the game. I would never walk up to the plate meeting with rulebook in hand - I just thought if it was mentioned ahead of time it would give either the opposing coach or umpire the more private chance to get clarification rather than in the heat of the moment. Keeps the crowd out of it as well.I had a pitcher that threw this pitch and this was my experience.
It was rare that an umpire was aware of this type of pitch and that it was legal. Most of the time the game was stopped so the umpires could confer. Sometimes the tournament director was brought in...sometimes they ruled it was illegal. At a certain point in the season our parents knew the pitch was legal and would start chirping at the umpire immediately that it was legal once the pitch was thrown. Arguments would ensue in the stands between our parents and their parents. It just wasn't worth the drama.
What I hated the most was how it disrupted the flow of the game. Some of the umpire delays were lengthy and it just wasn't worth it in the end. She only threw the pitch once or twice a game in certain situations and the juice wasn't worth the squeeze.
I would not advise bringing this up pregame because ultimately some coaches would protest/argue anyways once the pitch was thrown and the umpires generally don't like you brining a rulebook to the pregame meeting. When playing in tournament games you are always on the clock and it just wasn't worth constantly arguing about (knowing you were always in the right).