[crimsoneer]

Monaco has the highest number of police per head in the world (I think). It's also not a democracy, and can deal people quite harshly.

[mpclark]

...and practically speaking, it is really hard to get in and out of Monaco (there are only a few roads in and out and traffic moves slowly) and everywhere is covered by cameras. Anyone who tried a street robbery likely wouldn't make it very far at all.