Originally Posted by bairdco
another lesser known fact, a tinfoil helmet acts like an antenna. instead of shielding out the unwanted RF, EMF, cosmic rays, ether, the matrix, voices, walt disney's ghost, or whatever it is you're trying to hide from, you're actually amplifying the signal, straight into your brain.
build yourself a faraday cage, instead...
depends on the design really, people used to shoplift quite effectively from walmart and other stores with RF detectors by lining a bag with tinfoil. It has a specific name, and is listed in the "A" cook book (it's illegal to have), but just a random tin foil hat generally follows a parabolic shape and will focus right dead center in your brain.
Of course when it comes to an EMP discharge tin foil would be less than useful, I imagine if you're close enough to one it would have an effect very similar to tinfoil in the microwave (which is pretty spectacular, but... not recommended)