The same reason I won't hunt honey holes until November. The really big deer are nocternal for the most part unless someone jumps him (great hunting tactic in a late morning stand or early evening). They loose that safety net when they are nearing the rut. They go crazy since it's only a yearly thing. If you sneak into the woods early season, you will disrupt your big boys and possibly your Does. You want to hunt the Doe patterns in November and watch the action and make adjustments. I have been treated in years past of some good shows, but this last year took the cake.

There is also the second rut that will re-establish itself for all the un-pregnant Does but it is no where as strong. It will happen mid December and there is no cerntainty of the big one showing, so shoot what you want.