Redhat 5.2 on cd. I learned a lot about compiling kernels as it didn’t support scsi emulation which was required for an ide cd burner. I think I ended up on Mandrake for a while before bouncing around including LFS. Then gentoo for many many years. And I’ve come full circle and been back on fedora for about 10 years now.
I mean Amazon did this for their mp3s. It was literally just an id3 tag with a unique identifier. Not hard to remove but “good enough” to keep regular people from overly distributing it. You’ll never win against the real Pirate community no matter what you do, so just give people real incentive to buy and actually own.