I will be interviewing with Google in the upcoming months, I plan to share an interesting Idea for something I want to implement during my 20% time during the interview, because showing that one can come up with new product ideas has to help in an interview. In theory Google could then refuse to hire me, but implement my idea I presented to them and profit off of it without crediting me if they chose to.
Now I'm not really concerned about this, even assuming Google deemed my idea worth implementing I don't see Google trying to steal it (It's not worth the bad press that would result). Furthermore this particular idea is essentially only viable if implemented by Google, meaning even if the idea was stolen I wouldn't really be at a lost since I can't do anything with the idea without Google.
However, I am curious what the legal status would be if I was concerned about my idea being stolen. Would someone in the theoretical position of having someone implement a product they pitched (without getting a contract signed ahead of time) have any recourse to try to get recognition for their idea? Would there be any steps, short of forcing an interviewer to sign a contract before pitching your idea, someone in such a situation theoretically could take prior to presenting their idea to help ensure they got recognition for it?
I imagine the answer is no, but maybe I'm wrong :)