[Nicholas_C]

I would guess they take it to a chop shop and sell it for parts, but I'm not sure how plausible that is since they have GPS (or maybe they all get caught). Perhaps the thieves know the cars have GPS and can disable it in some way before they get to the chop shop.

[disbelief]

Maybe a chop-shop with a drive-in faraday cage?

[gavazzy]

Maybe they wrap the whole car in chainmail on the side of the road