A group of MIT students decided to test the performance of different tinfoil beanies to see how various designs (the "classical," "fez" and "centurion") interacted with commonly used industrial radio applications. They found that all three designs actually amplified these mind control rays radio waves, suggesting that the tinfoil hat meme might be a false-flag operation engineered to trick the wily and suspicious into making it easier to beam messages into their skulls.
Among a fringe community of paranoids, aluminum helmets serve as the protective measure of choice against invasive radio signals. We investigate the efficacy of three aluminum helmet designs on a sample group of four individuals. Using a $250,000 network analyser, we find that although on average all helmets attenuate invasive radio frequencies in either directions (either emanating from an outside source, or emanating from the cranium of the subject), certain frequencies are in fact greatly amplified. These amplified frequencies coincide with radio bands reserved for government use according to the Federal Communication Commission (FCC). Statistical evidence suggests the use of helmets may in fact enhance the government's invasive abilities. We speculate that the government may in fact have started the helmet craze for this reason.
… We evaluated the performance of three different helmet designs, commonly referred to as the Classical, the Fez, and the Centurion. These designs are portrayed in Figure 1. The helmets were made of Reynolds aluminium foil. As per best practices, all three designs were constructed with the double layering technique described elsewhere [2].
A radio-frequency test signal sweeping the ranges from 10 Khz to 3 Ghz was generated using an omnidirectional antenna attached to the Agilent 8714ET's signal generator.
On the Effectiveness of Aluminium Foil Helmets:
(via The Atlantic)