Why do you think it is security by assumption. Name a way of launching explorer (or other program) that I haven't mentioned here or on my blog that I haven't locked down and I will send you $5 by paypal. To cash in on this I will have to test your hack on our test system.

I have disabled autoplay.
I have disabled CTRL-ALT-DEL
I have disabled all keys with and popups with a minimalist theme and removed any excess modules.
I have disabled the run command in the LiteStep Source specificly the recoverymenu.cpp
And lastly the Flash program we developed also disables several keys that weren't caught elsewhere.

Good luck.