They will most likely use hardware ID to track installs. So if you reinstall the game on the same machine it won't count, if you install it on a different one it will. Unless they let you bind it to some internal ID and track it that way.
That would really suck for a small Unity dev to get screwed by a Windows update that forces reinstall of their users' game libraries - which isn't that uncommon.
Making the developer pay for user's hardware upgrades is still insane.
On the recent Intel platforms upgrading your CPU required upgrading your mobo too, and there are many people who upgrade almost every generation, i.e. 1-2 years. Burdening game developers with this is unjust. The engine fee should be tied to the game's purchase, or game related purchases(DLC, other paid content).
AMD also promised (iirc) that the AM5 will only be good for 2 generations.
Pretty trivial for a malicious user to spoof, but I wouldn't be surprised if it's something that calculates a new hardware id for trivial changes as we see so often with "don't install this on more than 1 computer" DRM implementations.
https://forum.unity.com/attachments/upload_2023-9-13_1-49-36...