> I don't think that it's totally impossible to copy such keys and it will be probably even be harder to prevent copys in the future (think 3d printing). But you can't have them copied by any old shoe maker with a key copy side business.

I remember a story recently about a secure luggage key. And every luggage lock was supposed to use it, but you weren't supposed to be able to get copies. But then a newspaper article printed a full-page image of the key, so... yeah, it got duplicated on a 3D printer that day: https://nakedsecurity.sophos.com/2015/09/11/tsa-master-lugga...