I'm dating a lawyer. According to them, what you've written is true, however, speaking practically, there is a significant advantage to be gained from presenti

I'm dating a lawyer. According to them, what you've written is true, however, speaking practically, there is a significant advantage to be gained from presenting evidence. If two parties show up to a dispute with identical source code, the one that has a copyright in it has an advantage. Sure, it's easily faked, and that could be argued, however, it would be trying to argue away evidence that exists which is much more difficult than arguing in favor of something that does exist. So if you want to lock in a victory and reduce court time, use copyright notices (and other legal notices like trespassing signs, etc.) liberally.