[Camron Rust]

Originally Posted by bob jenkins

I agree that's the penalty if a T is assessed.

In the OP -- if the C still had his/her hand up, waiting for B1 to leave, then the ball never became live, despite U2's best efforts. No T, reset everything, administer the throw-in.

If C dropped his hand, indicating play should resume, and the U2 administers the throw-in, then you have no choice but to assess the T.

(Of course, maybe it's a stretch to assume C used proper mechanics. So, change the above to "if C knew before the ball became live that B1 hadn't left, no T. Otherwise T.")

Exactly!