You mention "trust", "steal", "juiciest parts (of ideas)". You seem to imply that ideas (without execution) have a huge value and so must be protected somehow like a treasure. I think this is the fear that a hacker might listen, secretly record the conversation and swiftly run home to implement your idea before you. This is unlikely to happen. Chances are that if your idea is so good to get a hacker inspired to do something about it, a truly brilliant hacker might actually ask you if he can join you instead of going on his own. If he decides to "steal" it, chances are that he is not such a great hacker after all.
But anyway. An idea without execution is close to nothing. I don't think you have anything to fear to talk about it with anyone: non-tech people might help you to think outside-the-box and provide a different perspective; your peers might become interested, give implementation advice, or even join you. And you might as well talk about your idea at least to understand it's not shit.
If you keep your idea to yourself, it's just you and your brilliant, closed, lonely idea. :)