Down judge Dana McKenzie made good use of his bean bag in the Week 1 Monday Night Football game.
Fans normally see officials drop the bean bag to indicate a fumble, interception or another change of possession.
McKenzie used the bag for a more rare purpose (at least at the NFL level).
A play was going out of bounds and opponents appeared upset. McKenzie marked the out of bounds spot like normal, but saw that side judge Lo Van Pham might need help in quelling a tinderbox. So McKenzie dropped his bean bag at the out of bounds spot and went to the trouble spot.
Many high school crews use five officials. This mechanic is used a lot by the wing officials. The referee, umpire or back judge then comes in and covers the bean bag spot. Or if things are getting out of hand, they note the bean bag spot and wade into the melee.
Other times, if a player is injured and the officials need to move the ball in order for the trainers to give aid, they put the bean bag at the spot, and hold the ball until the injured player is moved. Or, if the chain gang is late in arriving to a spot in hurry up offense, the wing will drop the bean bag to show where the chains need to set up.
Before officials used bean bags, they used to drop their hats at the spots they wanted to mark. The bean bag is much less conspicuous.
Officials only have two feet to mark spots. Sometimes those feet need to be elsewhere. Then the bean bag becomes a valuable tool.