Most likely not; being sassy is probably the way a sorceress shows off her power without displaying it. If a gal in a robe or not wearing much is being a sassy bitch all over town, she's liable to end up poorly unless she's got the magic power to back it up. So it's a mark of her skills/power. The more powerful, the more sass. Of course should she be weakened/lose her powers, she'd still need to keep up the sass or people will suspect.