That would be a wise course of action. The first thing you should do though is write your idea down in pen on a piece of paper, and if you've already made a model of your idea or whatever, take a picture of yourself with it (preferably polaroid, though I know they're not really around anymore), put these things in an envelope, and mail it to yourself. What this will accomplish is the postal service will stamp the envelop, and part of that stamp will include a date on it. By doing this, if anyone attempts to claim your idea as their own, in court you can bring this letter with you, open it up, and that will prove to the court that you had the idea first, since you will have actual physical proof that it was your idea. When you get the letter, make sure you keep it in a very safe place, like a safe deposit box or something, as that is all you have in the world to show that this is indeed your idea, and no one else's.