Comment The Idea Marketplace (Score 1) 539
If vetting of your idea requires expertise that you yourself don't possess, you should be prepared to offer those you consult with a stake in the venture. Otherwise you'd be guilty of the very thing you seek to prevent.
If you are truly a serious inventor, journal your marketable thoughts, email, print and mail them to yourself to establish authorship. If possible, prototype the idea to establish prior art. Let those you discuss the idea with know the idea is documented and you should be protected as fully as the law allows.