The staff has not the time or ability to police these types of things. It would be a matter to be settled between you and the person who is using it. I'd recommend taking better care to make sure your code never got into the hands of someone you couldn't trust.

PirateHead wrote:

If you give it to them willingly, without making them sign a legally binding contract first, then you probably have no recourse.

Depends. You could claim that it was given in confidence under an implied verbal contract and that, in the absence of declaring it to be public domain, the original author retained copyright. Their distribution of the original source code would thus be copyright violation (since source code counts as a literary work). However, without the paper to back it up, it's legally impotent and the judge could really rule either way.

Of course, it's moot because a civil court would think this is too trivial, and it's not applicable at all to criminal court.

This only flies if the person contributed very little to the project, also. If they were a substantive contributor, they would have copyright to the work as well.