When you see flag down it is good to whistle, gotta let the R/HL know so we don't move the chains and so everyone else knows there is a penalty on the ground. Especially if they don't see it.

As the U I usually don't need a whistle, depends on the offense. I bring an extra coin and whistle for the absent minded R's though. Passes, sweeps and any dive outside the guards I am generally going to be quiet on. Teams that do a lot of tight dives I might have a couple but rare. Most of the crews up here alert the R to a flag with several short chirps of their whistle a few seconds after the covering official's whistle. The covering official hammers the whistle when he sees the ball has become dead so there is a distinction in the whistle. Multiple whistles may sound nice to stop action away from the play, but I fear it leads to IW problems. I have to see the ball to blow the whistle. We had 4 on side kicks to the U/LJ side last week and neither of us (the covering officials) blew the whistle because we had to dig for the ball each time and neither of us clearly saw a possession before the pile formed. We were glad because one time, after starting to dig, the R blew his whistle as a player from the kicking team was walking around with the ball about 15 yards away from the pile we were sure the ball was at the bottom of. The LJ and I were so sure we dug anyway to make sure it wasn't a 2nd ball trick. (Officaiting can make you so untrusting).