Super Munchkin card with Thief class

[ancillainvicta]

If a player is a Super Munchkin and only a Thief, does this mean a) that the penalty for failing an attempt at item theft as a Thief is a "disadvantage" to being a Thief and is therefore ignored by virtue of the Super Munchkin card, b) that theft is an advantage to being a Thief, and the penalties for the power backfiring are not covered by the Super Munchkin card, or c) some other possibility that my circle of gamer friends did not consider?