I'm not a lawyer, but is non-transferrable warranties even a thing? I've never had a single product where they asked me for identity to use the warranty. At worst, they asked for a proof of purchase, which some second-hand sellers are happy to provide when they still have it.

Also worth noting: hardware manufacturers have found a better option to suppress the second hand market. Hardware locking (iCloud/Knox lock) is terribly efficient at this, essentially turning perfectly good devices into bricks. It's even "better" because they can advertise it as a security feature for gullible users who don't realize Apple/Samsung still has the master key and there's an entire corrupt grey market of company workers getting money under the table to defeat the lock in almost every phone store across the planet...

Yes, many product segments have non-transferrable warranties. NVIDIA warranties are non-transferrable, as are Herman Miller warranties. That being said, you can have the original purchaser make the claim for you or you can pose as the original purchaser/doctor the receipts, but it creates a big hurdle for secondary markets.

I don't understand what you mean by iCloud/Knox lock. As far as iCloud lock is concerned, it is only for stolen devices in which the owner did not deactivate their own icloud account. Where are your sources for gray market of company workers defeating the lock? I'd imagine if an Apple activation lock is bypassed it would have to do with resetting the password on the iCloud account.