Hello. I'm in the market for a used iMac and Mac Mini at the moment, and I was recently in conversations with some guy to buy 'his' iMac. There were a bunch of red flags and holes in his story, and I decided not to go through with the purchase. But, it got me thinking: How should I go about ensuring that the Mac I want to buy is legit? Does Apple (or a former user) have the ability to lock down a computer if its serial number is reported as stolen? Is this something on-top of, or complementary to, the iCloud lock? The first thing that I plan on doing, regardless of my purchasing source, would be to boot from a USB stick containing an operating system installer (by pressing 'C' on boot-up). I would then erase the main/only drive on the computer using Disk Utility, and then I would install a fresh instance of the operating system. In this situation, would I ever run the risk of having my computer locked-down via Apple or the former user, in the future? Does Apple maintain a searchable database for blackballed Macs/iOS products? Thanks.