Communication among the crew is paramount in any situation where there is doubt. I had a game several years ago. Team A was riding a 39 game losing streak. They scored late in the game (less than a minute) and were down by one. They decided to go for 2. The play was a quick short pass over the middle that was low. It clearly skipped before the diving receiver scooped it up. The BJ was screened out of the play. The U turned and saw it (as did I at R). He immediately signaled incomplete. The two wings who came in and were looking only at each other at this moment were about to signal something. I started shouting NO, NO, NO to the them. To my complete horror as they looked at each other, they nodded and signalled a TD. The crowd went wild thinking the streak was about to end. I had to break the news to the very unhappy coach. They did recover the ensuing onside kick, but were not able to score. The place was going nuts as we left the field. As luck would have it the school was locked and we had to wait to enter the locker room. We waited for an eternity. During this time a player from the losing team eventually came up to me. He identified hinself as that receiver. He told me that I was right and the ball did in fact hit the ground before he caught it. I thanked him for his honesty and told him that he had a great deal of class. I then asked him if he would mind announcing that to the 5,000 people still yelling at me!
Years later I was working an adult flag game. I was downfield and ruled a no catch on a low pass. The receiver came up to me and said, "Do you remember me? I was that receiver in the high school game were you ruled a no catch." I told him that I did and he replied, "That's twice you were right. I've got to stay away from you!"