I know Frog=French.

Just saying, they know Pixies, and are the nation known to grant them SINs. Hell, they granted them self-rule. Just a little odd to have a Frog in that position.
You seem really set on the SIN being stolen and are ignoring the entire plausibility of the situation. At that point, you just say it was stolen and don't think about it any more. Done.
Kinda harsh. Yeah, that's the outcome I'm interested in, but I've been trying to argue logically as to how this might work, as opposed to just ignoring anything you guys say.. I'd envisioned the character in this way, as a citizen fallen rather than a pet escaped, which is a pretty different situation.
It is very hard to get rid of a SIN once you have one. Stipulating that some punk kid can steal it from you is a very bad precedent. It either means that your pixie is an utter moron or the entire infrastructure of SINs is compromised. Now, a FAKE SIN could be stolen like that since you can't just go to the cops.

A government system in Shadowrun not working how it should? Oh, the horror.
Eh, not really. Even if what I'm saying is true, it usually would get thwarted by the family, at least in most situations, or Corp middle management. Family Groups that don't have long term Matrix access are the flaw in the system, but those groups tend to be SINless, so what should the system care? And yeah, someone without much experiance in public living, going from small scale clan life to cities and sprawls? She had stuff to learn.
If you want a plausible reason for an educated pixie to be SINless in Seattle, that is a different matter. Being a pet works and it works pretty damn well if you're from Quebec where they hunt paranormals. And if you were registered under a CATco employee, when it went belly up, so did your meal ticket and registration. Perhaps your master was a secretary for Lucien Cross and died in that crash. No body to be identified. The corp gets bought up so nobody asks about her whereabouts. Just need to explain about 8 years of keeping a dead woman alive in the eyes of the SIN registry. You could even use those 8 years to better yourself, stealing from her coffers to pay for your education. Or, you know, you could just get mugged by a kid fresh off the boat and not realize you can just report it to the police... your call 

Erm.... I do appreciate the advice, but... well, the thing is, that simply results in a pretty much completely different character than the one I'd intended. I was after a character who'd studied Hermetic magic in Prague, become a member of the Benandanti, happy to get to see more of the world, who then got essentially marooned in Seattle, and had to take to dark paths because of it. As opposed to a liberated pet, who has everything to live for now. There's nothing inherantly wrong with that concept, but... well, as a thought, would it be fair to describe that character concept as somewhat 'Moe'?
Honestly? The idea that she doesn't believe she can talk with the police is probably more plausible than at first it seems

. With lesser knowledge of how these things work, it's not implausible that she'll believe that getting caught without a SIN in public gets her a criminal SIN. (In places like Quebec, it probably would)
Also, please tell me there's a Trid or at least a chapter in some sourcebook called 'SINless in Seattle'
