[NFHS] Violation on free throw shooter?

[upprdeck]

we have a player whose routine is to accept the ball and for some reason. he kicks one foot to multiple times on on the line like hs is trying to dry the floor, much like a batter does on his back foot in the dirt in baseball.. he often puts his foot 2-3 inches over the line and it has never been called in the two years i have watched him play.. of course i have seen players with their feet 4-5 inches over the line shoot shots with no call as well.