Interesting that this topic has just been brought up. Indiana's 3A girl's state final had a situation towards the end of game that had an inadvertent horn during a free throw. The lead official whistle the ball dead while the throw is in the air. He waived off the shot, which I thought at the time was something he didn't have the rules backing for. Here is the link, scroll to 1:41:53 to see the situation.
2014 IHSAA Girls Basketball 3A State Championship | Indiana High School Athletic Association Videos | iHigh.com