said by ISurfTooMuch :

Then why not just use a SIM card and be done with it? I mean, look at AT&T and T-Mobile. They sell devices, but they do nothing to prevent you from getting a handset somewhere else and using it. I can get a phone from them, from an independent retailer, or even from another carrie, provided it's unlocked.

But this is no surprise, given VZW's culture of control. One uniform OS with limited customizability, no ability to use your own audio files as ringtones unless you want to use a hack to get them onto the phone, and no ability to use whatever technologically-compatible phone you choose unless it's been blessed by VZW.