That's the catch though isn't it? It's only wilful infringement if there was intent. Just because you don't know the law, that doesn't make it allowed but it do

That's the catch though isn't it? It's only wilful infringement if there was intent. Just because you don't know the law, that doesn't make it allowed but it does make it unintentional. A license notice provides a clear explanation of the rights and responsibilities of the user. This dissuades most any notion of "lack of intent" as the restrictions are put in your face from the start.