The scanners at airports can certainly detect what kind of junk you have. There are tons of horror stories in trans communities. This one just seems like a hoax though.

I think it would be funny to put these stickers in front of every public restroom to scare the conservatives

You might have issues with permissions for serial ports on some distros, but there are loads of easy to follow guides for that. Linux definitely handles them better than windows though. I never had issues where they just stop working like on Windows.

I wish I could get diagnosed