[oneijoe]

I disagree, you see calls made in college and the NFL all the time where a hold or block in the back occurs nowhere near the play, but is still called. As it should be.

If you call the penalty regardless of whether it affects the play or not, then maybe the next time the offending player will think twice before holding again.

The vast majority of the time, the offending player doesn't even realize he's doing it. A lot of it is a result of poor technique and/or fatigue.

Contrary to what you imply, there's few times "thought" is involved in the process at all.