The CodeBank is a place where we share our work with others. Whether or not it gets credit in other people's applications is a risk we take. If we wanted to, we could sell them instead on a different site, but we offer our stuff free and open source. My latest two submissions, I've spent several weeks on them (one of them, over a month and a half), and I put them out so that way others won't have to go through the same stuff I have. Credit is optional, and they're really SDK's for making their own content around it.

It's common courtesy to give credit where credit's due, but posting a compiled EXE in the codebank is (as been stated) against the rules, and someone can just decompile it and get the source code anyway (or very close to it).