Apple distributed a document to authorized Apple Service Providers that advised of a pending policy for repair of products with the T2 security chip. The T2 chip is in the 2018 MacBook Pro and iMac Pro. The document states that the computer will be inoperative unless a proprietary Apple "system configuration" software is run after parts of the system are replaced. In other words, you're being forced to use an Apple approved repair facility instead of using someone else or even fixing it on your own.
Motherboard reported that iFixit has tested the repair process and determined that the lockout is not yet enabled. Apple does have a "kill switch," but hasn't enabled it at this time.
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Digital Forensics/Information Security/Information Technology