[just another ref]

I don't think there's any trick to it, you just have to pay close attention. Anything a player does casually, naturally is much more likely to be missed. In the posted video here, I think the player himself had forgotten, so it's not hard to imagine that the officials did too. Another one I have seen. A player tucks the ball under one arm and stands for an extended length of time to hold for the last shot. Just before time to start the last shot sequence, the ball handler will wipe both shoes clean. oops