Just like the GPL, copyright puts conditions on the disposal of a work. There are no physical restrictions in either case, just the idea that you honour these terms.
Would you feel comfortable walking past an artist trying to graft a living selling paintings/prints in a street stall, then against his wishes take a picture of them and tell him you're going to share these with your friends so they don't have to buy his work? Does that seem honourable to you?
Also consider a situation whereby two parties had a contract dictating the terms of how some artistic work could be used. There's obviously nothing wrong with this since both parties have agreed to the contract. Then say some third party illegally acquires the work and makes it available elsewhere. Seems fair that at this point we can rely upon copyright to protect the work of citizens. Just like you have privacy rights and defamation rights and so on.
Would you feel comfortable walking past an artist trying to graft a living selling paintings/prints in a street stall, then against his wishes take a picture of them and tell him you're going to share these with your friends so they don't have to buy his work? Does that seem honourable to you?
Also consider a situation whereby two parties had a contract dictating the terms of how some artistic work could be used. There's obviously nothing wrong with this since both parties have agreed to the contract. Then say some third party illegally acquires the work and makes it available elsewhere. Seems fair that at this point we can rely upon copyright to protect the work of citizens. Just like you have privacy rights and defamation rights and so on.