[Adam]

You're right, if it's an endline throwin and A1 bounce passes to A2 standing OOB, it's perfectly legal and there's a case play to back this up.

If, however, the bounce pass bounces OOB and is touched in bounds by a player or the floor, it is a throwin violation.

If the thrower is holding the ball and fumbles it in bounds (whether it rolls or bounces doens't really matter) it will only matter whether the ball hit the floor OOB prior to going in bounds. If it did, it's a violation. If it did not, it's legal.

I have called the bounce pass that hits OOB first; you just don't see it that much. I see it get close every once in a while, but hardly ever see it actually bounce OOB.