Wouldnt it then shift from being a copyright enforcement issue to a contract/license enforcement issue? I.e. you agreed to share your source code if you distribute, but now you didn't, so sue city?
But if there is no copyright, there is no need to license the software, you can just copy it without agreeing to anything. That's what it means for something to be in the public domain.
Contracts are only valid if there is an exchange of value; you could reasonably argue that there is no value in being granted a right you already have.
Contracts are only valid if there is an exchange of value; you could reasonably argue that there is no value in being granted a right you already have.