Hmmm. Yeah, OR you could just try selling a service (cell network) which people want to buy at a fair price and without all the hassle.
It's not like people were unlocking iPhones and stealing AT&T's product (cell network service). They were unlocking iPhones to use on OTHER networks because AT&T's product is so incredibly damned crappy, and their customer relations are so incredibly damned crappy, that the $200 early-cancelation fee plus hassle of voiding warranty and dealing with jailbreaking was worth it to customers.
Any time people are spending large amounts of money and time just to avoid buying your service there's more wrong with the world than people knowing how to slip through the cracks.
As expected, though, AT&T decided to tighten its grip instead of learn from its customers. Obviously, they are all just plain wrong, and would be much happier if they would just accept their jackbooted overlords.