[AtlUmpSteve]

The intent of the rule is this: If a runner commits an infraction (one of the two listed), and is advancing afterwards and is obstructed, she can be succesfully appealed for the infraction (missing a base, or leaving too early on a fly ball). If the runner commits an infraction, realizes it, and is attempting to return to correct the infraction, and is obstructed while returning, she cannot be succesfully appealed; she is protected because of her attempt to return.