[Ref in PA]

Who is to say the slap on the arm did not create an advantage?

Consider this. B1 gets the rebound, and has the ball protected. Players from both teams begin moving up court. B1 will now start to look for the outlet pass. A1 comes from behind, takes a swipe at the ball, gets all arm, and moves up court. B1 now hesitates because of the contact, takes an extra pivot to make sure he is clear. The swipe by A1 allowed team A to get back on defense, perhaps stopping a cherry picker lay up. In my mind, an advantage was gained by team A to be able to set up on defense. A lot of ground can be made up on a basketball court in a 1/2 second. Was the ball knocked loose? No. Was possession lost? No. But there are other advantages that can be gained. Just something to think about.