Difficulties

• "New IMEIs can be programmed into stolen handsets and 10% of IMEIs are not unique." According to a BT-Cellnet spokesman quoted by the BBC.
  
  
  
•  Facilities do not exist to unblock numbers listed in error on all networks. This is possible in the UK, however, where the user who initially blocked the IMEI must quote a password chosen at the time the block was applied.