I would assume locks to HW are done on unique chip identifiers like on other platforms, whether it be a MAC addy, CPU serial identifiers, BIOS, various firmwares, etc. Not quite sure how MOS does it, to be fair. Windows does it in a similar fashion where you generally must call MS to decommission a license, which I recently had to do on an old core 2 quad PC I repurposed from Vista to Linux. Took 3 minutes on the phone to do.
AFAIK, there has not been any upgrade fee on the 4.x OS 4 updates, yet anyways. I've not paid a dime thus far anyways, but my SAM came with 4.1 and the only updates have essentially been small "service packs" like u1, u2, u3 so far. I would not have paid for any of the u1, u2, u3 packs if they were pay for, tbh - and likely won't pay for 4.2 if they decided to charge for that upgrade. The OS is immature (OS4 - albeit fun), so justifying payment for what is essentially bugfixes is hard to warrant.
I fail to see the difference in a "broken down" machine and a decommissioned machine, I suppose, heh. Either way, it's a Mac no longer using the software that was paid for. What is the criteria in such a case? Not sure what the developers would require as "proof" that a machine is no longer at all functional, and what would be preventing from an otherwise honest guy like me from simply saying "it's broken" and demanding a license transfer and putting said machine on a shelf, never to be used again with MOS or anything else. Once said license was transferred it couldn't run regged MOS anyways, no different than a broken machine in the end.
