How about a convertible hat, where from the outside it looks normal, but when you lift a layer, it reveals the metal. Also below the metal would be cushion material layer for a good fit.

You are worried about arc flash, especially if another solar storm of Carrington Event size occurs.

You use it to improve reception from your personal satellite.

You're preparing for a head-sized electrical outlet.

You see safety issues, I gather. Like, I bump into a live wire while wearing my "tin foil" hat and get electrocuted? That depends on the material of construction. The sort of aluminized mylar I salvage from hot/cold bags is nonconducting (i.e., safe) on both sides. However, double-bubble building foil is quite conductive, both sides. 

To deal with Havana issues, the crown of your tin foil hat should conceal an all-perils dosimeter. In principle, such a device could be based on calorimetry—simple heat deposition, taking advantage of the fact that all forms of energy inevitably become heat.

Conductive fabric! Great idea. The SLs will be sore as hell.

For a fashionable and interesting hall costume at the local con.

There are quite a few very nice looking tinfoil hat art projects, do an image search to find these. One that I liked was a traditional "derby" hat made from wadded and crushed tinfoil. Despite the composition, it was the right size and shape as a derby hat that made it look stylish.

Depending on circumstances, one could wear such a hat (well-made artistic tinfoil hat, such as the derby) to public functions to gather esteem and interest from the viewing audience. Any news writeups of the (for example) conference would most likely include you and your hat, which would help promote you and the paper you present, for example. It's a way of standing out and encouraging comment, without the explicitly fringe homemade version of the hat.

Also of note: the ozone hole starts at the South pole and creeps Northward each year, depending on the size of the hole that year. Because of this, the "logic" of wearing a tinfoil hat for this reason fails: you'd have to be living in the Falkland Islands or similar for this to make sense.

The ozone wording has been tightened up. Please excuse the lack of clarity.

Double-bubble building foil seems promising as hat-making material. It seems to have the right amount of stiffness for the brims, at least.

The 3 Best Explanations for the Havana Syndrome

https://www.youtube.com/watch?v=g9C3ZKWLZG4

But a tinfoil hat (using aluminium in europe) is just stylish and that's really enough reason to get one!

https://de.wikipedia.org/wiki/Datei:30C3_TinFoil-Hat_02_(cropped).jpg

Thank you. I just saw the you tube. So, not mass hysteria, but--- microwaves or ultrasound?

Does it have to be one or the other? A variable mixture would be harder to diagnose than any pure intervention.

Postscript: do not use corner-cube reflectors to return beams of whatever to their source because retaliation in kind is bad for the soul.

That's the video that still leaves questions.  I'd use that to sell "tin" foil hats until buyers ask about the updated information flying through the nets:  https://www.nytimes.com/2022/01/20/us/politics/havana-syndrome-cia-report.html and https://www.youtube.com/watch?v=ljf1TVWTSlQ

Then just put CIA and some smileys near to these 3 letters in the answers, and you will still be able to sell lots of hats.  \o/

𝔅𝔲𝔱 𝔫𝔬𝔴 𝔣𝔬𝔯 𝔰𝔬𝔪𝔢𝔱𝔥𝔦𝔫𝔤 𝔠𝔬𝔪𝔭𝔩𝔢𝔱𝔢𝔩𝔶 𝔡𝔦𝔣𝔣𝔢𝔯𝔢𝔫𝔱...
How durable are tin and aluminium in an environment with sweat and other probably not pH neutral moisture?  High tech hot fix:  Use the still top secret formula wire fabric that no longer contains tin or aluminium and additionally blocks the and aliens' (space lizards!) telepathy!

𝔄𝔫𝔡 𝔫𝔬𝔴 𝔧𝔲𝔰𝔱 𝔣𝔬𝔯 𝔣𝔲𝔫...
Someone really should translate this.  Maybe until then auto translated subtitles are good enough: https://www.youtube.com/watch?v=MvVQ1RK_kkQ

It would also troll a fair segment of the population for a little added entertainment