So my takeaway from this is pitch within the rules because you never know when they are going to be enforced.
If you want to cut corners and dare I say cheat then your rolling the dice and have to deal with what comes your way.
It does suck because it interrupts the flow of the game when illegal pitches are called. The home plate umpire always looks dumbfounded.
Have a group of umpires in our area that called around 5 illegal pitches on an 9U pitcher. She was about an inch off the ground sometimes. The same crew had a HS pitcher that was much worse leaping every pitch and wouldn't call it. The HS team played in the playoffs on the road and they pulled the pitcher in the 1st due to illegal pitches. Scared of not getting hired back maybe!