titaniumdecoy

Are the GPL, BSD, etc. licenses actually enforced?

Say you put your "work" on a website and label it as one of the above licenses. A few months later, a random person (Mr. X) rips off your "work" and puts it on his website, perhaps under a different license. Now what? The date you released the "work" and licensed it is not officially recorded anywhere. Even if you were to hire a lawyer (and for most people this is not an option, either for monetary reasons, or because they can't be bothered, or because there is no guarantee that they will get a return on their money), how would he/she prove your case, and to who?