I'm a member of the Spyderco forum and every once in a while someone will post their drawings of a knife for Spyderco to produce. Sal Glesser has stated that if you want to keep your idea from being stolen then do not post it and has a very very small chance of Spyderco producing it. If you want Spyderco to have a look at a design then have a knife maker or yourself make the design into an actual knife and send it in to Spyderco. I don't know about the big or small MT boys but Spyderco is not known to steal a design.
I think it basically comes down to, if you have big plans for your design then don't post it on a forum. If not go wild which I enjoy steeling ideas from btw

Unfortunately I'm not the owner operator of any company so I won't be mass producing anything anytime soon.