Unless you explicitly stated that the code was free for all purposes, you retain the right to pursue any of the people in your examples who used your code for copyright infringement.
They all took a chance by using your code, and they lucked out that you were happy with that. But you do still retain the right to pursue them.
I don't like doing that to my users - I'd rather that they can be secure in the knowledge that I intended the code to be free and they have a right to do what they will with it. That requires that I post a licence.