Under NBA rules inside 2 mins the refs can trigger replay if there is doubt about the play, specifically regarding the Restricted Area. In replay the refs can determine 1) wether the feet were inside/outside the RA, 2) whether the defender had LGP, and 3) if any other uncalled illegal acts took place (leading elbow PC foul for example). This allows them to essentially re-referee the play on video.

The Trail official did make a half-assed blocking signal, but a blarge does not trigger a review in and of itself. They must go to review the RA.