Well I'm going to be even more rigidly biased after watching the Saints/49ers and the no call on the offsides to end the game but I think it's got to be enforced no matter how slight it is once the rule has been made. The thing that drives most fans nuts in the inconsistency to which leagues/refs call fouls. And even one inch forward can be so much more when you consider that the offending player most likely started that burst of movement sooner. I'm all for it being just the feet and not hands, heads, shoulders, and hips but it needs to be called whether it's 10 feet or one inch.