Just in case you have never heard of something known as AFDB (Aluminium Foil Deflector Beanie)..
http://zapatopi.net/afdb/

The following article appears to show that wearing an AFDB may actually be *worse* than not wearing one!
http://www.theatlantic.com/health/archive/2012/09/tin-foil-hats-actually-make-it-easier-for-the-government-to-track-your-thoughts/262998/