How about downloaded binaries not compiled from source, it would make sense to not have to sign code you compile your self. After all you know where that came from. In the end Gatekeeper is there to add trust to binaries from someone else. There are some solid arguments why certificates is a good strategy for Apple on this blog (made before Gatekeeper was announced). http://blog.wilshipley.com/2011/11/real-security-in-mac-os-x-requires.html
You're clearly arguing without even reading my post : downloaded and unsigned binaries, executed through normal exec() like bash does, launch without any problems.
It seems to only apply to Cocoa built binaries launched in the Cocoa runtime. Stop arguing and go try it. You always do this, can't ever accept that maybe, just maybe, you might not be understanding the issues being discussed, same as in the programming forum when you argued with both me and chown33 for pages...