Someone gets overly enthusiastic about the idea, tells someone, who tells someone else, who just happens to be looking for an idea for a post-doc, or even a grad thesis. Sounds paranoid maybe, but that's what I believe happened to me before, so there you go.

But you're right, I've posted it to a public forum. However, similar ideas are flying around, most notably laser trapped mirrors which is more about using standing waves to trap mirrors of molecular thickness. Which idea is more sound is really not much of an issue to me, it's kindof obvious. But I refuse to compete with these people anymore, since they are already in a position to benefit from whatever comes their way, from whomever, regardless of their own level of creativity. They're all about power. That's the real world.