I like the idea of asking for advice on possible dangerous ideas.

But I'd like to improve on the means: Just inviting arbitrary private communication isn't exactly save. Now OK, LW isn't really arbitrary, but telling 7 people replying on an open post... If the idea really were dangerous... Framing the idea in such a way at least causes curiousity and I had to restrain myself a bit to not immediately jump to the "Send message" button.

A solution could involve trusted rationality counselors. A proxy for this on LW could be contributors with high karma and and high positive rating.

ADDED: I think a wiki page "Rationality counseling" might be a good idea.