Creepy things goin on over here

[Ivan2006]

Please do not ever use tinfoil hats, the chance of them resonating and therefore acting as an amplifier is over 10 times greater than them having a considerable effect at stopping EM waves.

This is only very partially true.

Source: I know antenna theory

Well, my point is that for tinfoil hats to be an actual protection, they'd need to maka a faraday cage or something comparable.
A simple hat is pretty useless.
Therefore, there is a very low chance of it ever stopping any EM waves that would not otherwise be stopped by your skin anyway.
What I was trying to convey was that even the low chance of it acting as an antenna or resonator is still higher than it actually stopping any waves from reaching your brain.

[Tau]

That is a pretty good point.

[Ivan2006]

Of course, that only works if we're talking about EM-waves.
Any other form of wave energy we do not know about, well, we simply don't know anything about, so noone could predict the effects of a tinfiol hat.

Conclusion: a tinfiol hat won't do much except for making you look stupid and getting the Freemasons back into the white house.