Apple technicians stop repairing iPhones reported stolen or lost, according to MacRumors. Η εταιρεία απέστελλε μια οδηγία στα Apple Stores and authorized carriers not to accept devices for repair if they are recorded in their internal MobileGenius or GSX systems as stolen or lost.

This means that the technicians will check the IMEI once devices in relation to the GSMA Device Registry if a customer wants to repair it.
The GSMA Registry is a global database where owners can register the IMEI of their devices and set a status for them if they are lost or stolen. This n movement extends Apple's existing policy of blocking repairs for devices whose owners cannot turn off Find My iPhone.
This could perhaps discourage some from buying used devices except official and authorized sources so they don't unknowingly end up with a stolen phone.
Of course everyone can go to a repair shop (unauthorized) who does not care where they got their devices from.
