Camera men are always trying to spot any unique sighting on the sidelines. I bet he let the camera linger there, and his brain processed what was happening, and then the control truck guys (who decide what shots we see) also had a second or two of processing what he was doing...and SHAZAAM! the camera cut away and lots of people are guffawing over it.
I remember this man and woman who thought nobody could see what they were doing way up in the top of the stands at a baseball game. I won't post the link, but it is a HILARIOUS video. The camera guy just zeroed in on the couple and caught the whole thing.