Yep, it sounds to me that if a unit suffering stupidity accidentally makes contact with another unit's front arc, the other player can choose to either A, commit to the combat (neither side counts as having charged) or B, give ground until there is an inch separating them from the unit suffering from stupidity. If the contact is to the flank or rear, or if the contacted unit is already in a fight, the contacted unit (and whoever they're fighting) must be nudged an inch away from the unit with stupidity.
It sounds like there is no instance where a unit who has failed their leadership test for stupidity would ever count as having charged.