You can write whatever words you want on a piece of paper or uploaded to the info section of a GitHub repo. That doesn't mean anyone has to follow it. If it's

You can write whatever words you want on a piece of paper or uploaded to the info section of a GitHub repo. That doesn't mean anyone has to follow it. If it's legal to train on other people's stuff, without their permission, this would still apply to your code even if your code includes a license that said "I double extra declare that you can't train AI on this!!".