Even if you did name it, you wouldn't, sadly, be infringing on any copyright as this isn't a video game and/or article of clothing. BUT HOW DID THEY? WHY? CAPS LOCK CONFUSED MODE INITIATED!
How do i know which country the user registered from, and can i add a country field durring th registration?
You can attempt to locate them based on their IP, which is stored in the db, but there's no guarantee it will be accurate.
You can add a field to registration using a plugin, no way to do it in core.