The MIT paper linked in the second answer (http://web.archive.org/web/20100708230258/http://people.csai...) is a great read on its own.

Putting fashion aside, probably useful for both UV blocking (turn the hat into a hijab for better coverage) and also should reflect IR so reduce the chance of heatstroke when working in the sun. Disclaimer: avoid working/exercise in hot/humid conditions at all! Work at dusk/dawn or even wait for a cool day.

They can block incoming interest from romantic partners.

Of course they can. They block a frequency range. Is that useful? Probably not.

Yes! Microwave attacks like against international embassy workers are FOILED by aluminum hats.

https://www.nytimes.com/2018/09/01/science/sonic-attack-cuba...

What about tinfoil covered walls? Would living next to a couple of 4G/5G towers be improved by tinfoiling the walls in that direction or a full faraday cage setup is needed?

The top answer is gold. Short, and worth the read; gave me a good laugh.

Like other hats, tin foil would be effective in preventing sunlight burning your skin and causing melanoma etc.

Would be a useful material to have in a desert island scenario.

probably not too many have actually used a room-sized tin foil hat, but i have - we used to have a faraday cage enclosing our coulter counter (measured cells in liquid) at university of london, back in the early 80s. room to sit in and do stuff. don't know if this is necessary any more?

My longitudinal study has found that tin foil hats, when prepared and worn as directed, block 100% alien parasitical freqencies, 97.8132% of the attempts by FEDGOV to take over the minds of minunderstood scientists, and 2.091234% of the people who use verbal frequencies to ask questions about where to obtain their own tin foil hats.

d2. h4x02 f023v32

They can block water but not much RF

> While the underlying concept is good, the typical foil helmet fails in design and execution.

8-)

They can block someone finding a mate and procreating

It's a joke that as far as I know I am the only person finds funny but I've always thought that tin-foil hats need a grounding strap as otherwise they would act more like an antenna dish than a shield.

The approach of women. Very effective birth control. See [0].

[0] https://en.wikipedia.org/wiki/GI_glasses