Thanks for posting the abstract (I hope GoFIRST gets them all up soon...)!
I agree that scouting isn't terribly beneficial on practice day, with one exception - it's great practice for your scouters! It gives you a chance to go through your process in a real setting, get the kinks worked out, and then chuck all that data at the end of the day
. After all, there's no point in downgrading teams that don't show up during practice day, or upgrading teams that make it there all the time - if a team does well on practice day, they had better keep doing well the rest of the competition to be worth noting!