The IMEI is more then just the device make/model. It's more akin to a MAC address. <a href="http://en.wikipedia.org/wiki/International_Mobile_Station_Equipment_Identity" rel="nofollow">http://en.wikipedia.org/wiki/International_Mobile_Station_Eq...</a><p>Which is essentially like having a device finger print that's authenticated by VZW's towers. It's essentially their unique key to map data too, removing much the anonymity. Additionally Verizon knows which accounts have what IMEI's activated at any given time.