If her goal is to distract men while she robs them blind, she wouldn't be wearing armour at all.
Well, that isn't the most stealthy way to pickpocket guys in the streets... What I mean is that there would be a balance there, something "hiding" enough that one could easily walk unnoticed in the street, but all the while revealing enough to draw attention away from the thieving hands.
It seems like a weird strategy to me, but then I'm not a thief and couldn't tell you what a good thieving strategy is so... *shrugs*
But now you've reminded me of Isabela in Dragon Age 2. Which is kind of my one exception to the no-skimpy-armour rule, because damn. For all the game's flaws, the characters were wonderful, including Isabela. So really, I do understand that there can be exceptions to the rule, but you need to make me love the character for it before I'll accept it. But then, regardless of eye candy, Bioware knows how to write good female characters imho.