Since people were able to figure that out, then people could use that knowledge to create fake watermarks that decode to other people. If someone in the allianc

Since people were able to figure that out, then people could use that knowledge to create fake watermarks that decode to other people. If someone in the alliance wanted to frame another person in the alliance as a leaker, then they could do it easily with this knowledge. People that make systems like this should make sure the hidden value is signed or encrypted in a way using a hidden key so that people can't make fake watermarks for other users.