What Alex said. I can't see any way of a thief being able to get it out quickly to be honest. It'd take a professional to remove it because it's built in pretty tight.
My husband thinks my intellilink is spot on and he asked the woman at the dealers if he could have one put in his Insignia but she said they're only for Adams at the moment, so I assume it'd be pointless stealing one because it wont work in any other car
As I believe it car radios are matched to the cars body control module. They don't have codes as such but only work on the car they are matched to, hence you can disconnect the battery without needing to re enter a code.