I recently bought a Droid from Verizon. Previously, I had an iPhone from AT&T. My partner has an old AT&T account with a junky phone that we just wanted to keep the number from. I called up AT&T and explained the situation. They told me that I was required to keep both accounts or delete one, but that I was not allowed to move any numbers from any account to any other.
That seemed odd. So I asked what they would do if the number I wanted to bring in was a Verizon number. They told me that they'd be thrilled to move a number in and replace my current number at no charge and with my current plan. Wait... so, if I were a Verizon customer, I'd get better AT&T service, but because I'm an AT&T customer, they're not even willing to just move a phone number?! No, I had to have heard that wrong. So, I asked to speak to a manager and made it quite clear that all I wanted to do was move a number, not an account and that I wanted to keep my high-priced AT&T iPhone service for a good long time. Nope. I'd have to get a new plan with a new contract.
When I explained that my life would actually be simpler if I payed the $150 to terminate the iPhone and get my partner a Droid, I was told that that was my only workable option and he didn't even try to keep me as a customer.
In the end AT&T would much rather that you become a Verizon customer than close one, old clunky account and move the number around internally. Your customer loyalty for 10 years isn't, it turns out, worth a database record update to AT&T.
Well, two Droids is better than one, I guess...