Tip signal...

[blindzebra]

Is the signal in the book?

There is no need to use it on a shot, it's either a clean block...no whistle, or a foul.

Referee magazine had an illustration about a pass coming from lead's corner that gets tipped into the backcourt, and they suggested that lead come off the endline using the tipped signal to aide trail with the back court call.

There is debate about even using it then.

Don't use the signal and the problem goes away.

Also where is A1's shot coming from that both you and your partner are watching it?