[greymule]

Perhaps enforcing [insert any other ASA Rule here] is overofficious too?

Not all rules are equal, and nobody expects the umpire to pick every nit on the field. At some point the spirit of the rule comes into play.

Batter singles to the outfield and takes her turn around 1B. The ball goes to the pitcher in the circle, and the runner stops and returns immediately to 1B. With play stopped and the next batter entering the box, the runner on 1B positions herself to leave with the release. You as BU notice that as she is placing her foot on the 2B side of the bag, for a half second there's an inch of space between her foot and the base. You bang her out for violating the look-back rule.

That's correct according to the rule book, but it is not good umpiring. It's overofficiating, using bad judgment, whatever you want to call it.