Yes, very good point about the TO. I was trying to make a similar point about A1 and B1 crashing while going after the ball. If it's not an interrupted dribble, then the official MUST call a foul on B1 for contact without establishing LGP, but that clearly cannot be the case, since both are going after the ball. If we decide incidental contact, then it MUST be an interrupted dribble.

Eric,
I see your point, but I don't think LGP is always necessary to draw a pc foul. Not having LGP merely puts the "greater responsibility" on the defender; not 100% of it.

True. The biggest example of this could be the dribbler pushing off with an arm. LGP means nothing as to how you would call this play. The dribbler can't just crash into a defender who has a legal position on the floor either, even though that legal position doesn't include LGP. Casebook play 10.6.1SitE points that out nicely.

One thing to think about...can the player dribble or not?

NFHS Case Book, under Rule 7;
If A1 tips a ball before going OOB, he/she can return inbounds, secure the ball AND dribble.

If A1 controls the ball before going OOB (i.e. grabs it and throws it inbounds before falling OOB), he/she can return inbounds and secure the ball BUT CANNOT dribble.

This situation is confused a lot! Being a new official, I have friends and coaches who ask, "What about..." This has been one of those subjects. Unfortunately, officials often have differing opinions on this, even though the rules book and case book - for NFHS - seem to make it clear.