As a varsity U I have not been knocked down in 3 years, a lot of close calls though. The only time I was down was when I voluntarily went chest first to the ground when my feet got tangled and the QB and rusher were coming at me fast (as Referee in Flag football) they jumped over me and then I jumped up quick like a grass cutter
. I am rather large (yes, I do perpetuate the large umpire stereotype) and have knocked down more than a few people, but knowing where to go and when is the issue, so I think others will just have to learn.
This sounds too weird! half of the reason of an umpire is in the defensive backfield is to help control the trenches, and be right on top of the ball when it comes down to prevent extracurricular activities; being 3-4 seconds away on a 5-10 yd rush down the middle could be a greenlight for extras!