This is a myth, a BP isn't going to mistake your hand for a rodent. You are actually more likely to get bit when moving your BP to and from the feeding tub.We put her in a separate tub to feed her as we heard this is a good way to avoid getting bitten when sticking your hands in their tanks
Moving a BP to a separate feeding tub can also stress the BP out (this is on a case by case basis) Most people will advise you to just feed in the enclosure. Either way is fine but if your Bp stops eating your best shot is to try feeding in her cage.