This is very true. Having watched them it's not a simple matter of dragging a shadow across the field as light responds differently to different colors (as explained to us by the guy working on lighting). Each person in the crowd has a code and making the shadow go across individuals is tedious, time consuming.
We're getting to the point though that some of the things we are picking out are so trivial that it's a head scratcher. And we must keep in mind that they can't get everything we want in the game. Believe me, these guys know every gripe that we have, some of it over and over again.