Apple has created an online tool that lets iPhone users and potential customers check the Activation Lock of a handset.
Activation Lock is an aspect of the ‘Find My iPhone’ service. Whenever a customer loses their iPhone or iPad (running iOS7 and above) and activates the Find My iPhone service, the Activation Lock will prevent anyone else from erasing or using the phone without the customer’s Apple ID and password.
It’s now possible to see if ‘Find My iPhone’ has been activated on any iPhone if the IMEI or Apple serial number is known.
This reduces the risk of a customer unwittingly buying a stolen iPhone that turns out to be worthless.
[Apple: Check Activation Lock Status]