on crew's thought process.....
This works very well as long as the contact is not too excessive and if A2 does not immediately come back trying to retaliate. If both players just play on and the basket goes in, you can pass on the call and the next time that you are within earshot of B1 tell him that he needs to clean up his rebounding play.
If the ball does not go in, and the rebound goes to the other side of the floor (therefore B1 and A2 would not have any significant part of the rebounding play), you can still use the same logic. However, if the rebounding action on the miss comes to the side of the floor where B1 gained an advantage, CALL THE FOUL.....even if it is a late whistle from when the contact occurred.
More than once I have had the coach saying that "nobody is even near B1, how can that be a foul?" My reply is "Coach, how do you think it came to be that nobody was even near him?"
He then understands that the early push gave his player the freedom for the uncontested rebound.
Many here will disagree with this philosophy. However, if you try to use it, you may find that your flow will be much better for the entire game and that you are able to keep some good post players in the game a lot longer.