High school rules.
How many of us sound our whistle for every free throw air ball violation? Or do some us only sound our whistle for air ball free throw violations when there will be rebounders (i.e., not for the first of two, or not for a technical foul free throw as in the video)? If so, why not for every free throw air ball violation (it is a violation)? Not to embarrass the free throw shooter more than he already is? After all, the scorekeeper and everybody else in the gym knows that the airball free throw was definitely unsuccessful so no whistle is needed (although it's probably required).
Another free throw whistle question.
How many of us sound our whistle before a free throw following a timeout (as we do before a throwin following a timeout, or intermission)?
For me, I only whistle air ball free throw violations when there will be rebounders; and I almost never whistle before a free throw following a timeout. Right or wrong, this (both) is what most of us do here in my little corner of Connecticut.