> My code is not theirs and this is the core issue.
This is _exactly_ why a lot of jurisdictions assign/assume copyright by default, and make it hard to 'remove'. Otherwise authors would see their work ripped off in a lot of inventive ways.
When the default state is that every work is copyrighted, that removes a lot of possible confusion, and possible excuses.
Right. Under the older copyright regime in the US, you more or less had to add the appropriate incantation/symbols and send a copy to the Library of Congress or you pretty much had no leg to stand on collecting compensation if Disney or whoever decided to rip you off. The US decided that wasn't a good thing and that works should be copyrighted automatically. (Registration still has some benefits for collecting on copyright claims.) But that also means you now need to get rid of that automatic copyright, assuming you can, if you want to do so.
This is _exactly_ why a lot of jurisdictions assign/assume copyright by default, and make it hard to 'remove'. Otherwise authors would see their work ripped off in a lot of inventive ways.
When the default state is that every work is copyrighted, that removes a lot of possible confusion, and possible excuses.