I remember not being able to take fruit home from New York because I traveled through Ontario, and there's a ban on produce crossing the border from Canada into the US. Not that they likely would've known, but I was paranoid they had the drug dogs trained to sniff out produce too.
The USDA is very serious about quarantining. Growing up in Michigan, whenever my parents and I crossed the Mackinac Bridge we'd turn on the radio alerts, and there was always an announcement that there was a ban on transporting firewood between the Lower and Upper Peninsulas in order to prevent the spread of the emerald ash borer. The idea being that even one contaminated log could start an infestation.
It used to be that you could cross between Canada and the US with a regular driver's license, but now you need either an enhanced license or a passport. Soon you'll also need a special driver's license to board domestic flights.
Right... because when I was a kid, my uncle used to take us out on Lake Michigan and we'd go up to Canada that way and back without much fuss. I've never really crossed borders via road, though.
Actually, the only thing that wasn't stolen at the Louvre's Apollo Gallery is the Regent Diamond, figure no one would take it because something to do with a curse.
I've also found that the two thieves were leaving for Algeria, thanks of a trace of DNA evidence recovered from a helmet and their past in burglary cases according to the police.