My DD has only played club for a short time, but the only few times I've seen an crow-hop called was when the there was when the drive foot left the ground. Interesting video that I found when I was watching Gabbie Plain from Washington. DD's pitching coach has her keeping the glove and ball married longer in the windup, so I was looking for a current RHP that does this. Plain is one that does and I found this slow motion video of multiple pitches and you can clearly see a redrive before she slides. I've watch quite a few of her games and have not seen it called.