Interesting,
I seem to recall that with old Fiat's you had the red key fob for general use and the blue for emergencies and I remember Mike Brewer saying on a show that if they have the blue only walk away, this was because it's the spare and they have most likely knicked it during a burglary and the car is hot. Same advise here, 1 key fob, simple spare key, if they have this for sale and no fob, chances are it's hot. That's how I treat it. Also, doesn't opening the car via key only allow you to drive the car in limp mode and for a limited milage? Don't ask where I read it, could have been on this forum.
Disclaimer: I may be totally wrong, take what I have said with a pinch of salt. On the other hand, I could have a point.
ED