Earlier quoted context omitted.
Have this scenario actually played out in court, or are you just speculating what would happen?
Suppose that Alice is an innocent bystander who has done nothing more than publish some innocent data encrypted with a one-time pad and Bob is a pirate who xors a copyrighted work with Alice's data and publishes it. Or vice versa. Anybody who downloads both of them can xor them together and get the copyrighted work, but only one of them was actually derived from the copyrighted work, and you don't know which one. The…
The whole xor scheme is irrelevant. If you give people a file and the information about what other file to xor it with to get the cleartext, that is just the same as giving them the cleartext straight away.