I think they have to look at all shots that go in at the end of the game. They might have been looking to make sure it was a catch and shoot. If they did not look at this play, they might have gotten hammered from all sides. Remember they have replay, we do not. Different set of standards, even though the rule that we have was created by the NBA on some level. (Trent Tucker with the Knicks against the Bulls I believe)
Peace