I'm about to declare this horse dead, and dead again. There are going to be plays where 7 yards down field is a foul, and 6 1/2 will not be. The man standing somewhere is going to make that decession in about 1/2 a second. As long as he does it with the intent of the rule to protect the blockee, and not to declare some stripe on the field as a line of demarkation, ( and how many times have you been off a yard) we are doing our job. It's kinda like porn, you know it when you see it.