try starting a IS-95 or CDMA-2000 carrier in Europe...not legally possible. There are advantages to the Euro approach, but there are disadvantages, too.
It would be possible to use a SIM-style approach for CDMA (maybe they do in Korea), but this doesn't help for GSM/CDMA phone swapping.
If the phone is subsidized by the carrier, then the carrier should have the right to lock it. I've heard it's easy to get it unlocked, e.g. if you're going to Asia. Plus, there are plenty of companies that will do it for you.
--Tony