How is it anywhere close to being a clever check?

Im sorry, thats not a clever check. That's not even close. It's highschool introduction to programming level "clever".

wondering out loud.

In the past with these CD referene libraries, you could either install a stub on the machine and have it use the CD as the store, or you could install the whole library on the hard disk for faster access. Presumably this check is to prevent "piracy" by ensuring that the user has the CD but allowing it to operate faster with the on hard disk db.

However, since its check is so superficial, one doesn't even have to bother installing it fully. Image the. CD, keep the CD image on your hard disk, and keep the CD image mounted as a drive and install in the thin install manner that expects the CD to be present. Performance should be basically the same (its just going to be reading off the hard drive), even if it takes slightly more storage in the modern world the 10s of MBs this might be are close to irrelevant.

Echo other comments here. As an ex games cracker for some pretty large scale piracy orgs in the 90s I lol’ed at this