The only thing that I can see that would achieve would be to reduce the chances of someone linking that device to this BBS. Of course, that would also require a custom boot logo, and still wouldn't completely remove traceability - the player software contains enough information to work out what it is. (during boot and via 'About').

I can't see why that would be a useful thing to do. Even if someone was fencing a stolen unit, the buyer would need some software to upload tracks...

And if I were trying to remove serial number traceability, I'd start with the sticker on the bottom, and also remove the serial number box to try and make it appear that maybe it didn't have a serial number at all.

I think it's just a personal preference thing. Maybe that text got scratched somehow and he decided it looked better like that.