This spunds like frequency illusion https://en.wikipedia.org/wiki/Frequency_illusion

Also maybe people started using them in spite of these articles–it’s kinda fun!

Rtlsdr too

So I still don’t quite understand patents,

Does it forbid someone from selling the intention? Making the invention? Can I not even make an invention for personal use if it’s patented??

There’s a dozen ways they could jump the air gap.

Ultrasonic to a phone or Alexa/Siri/etc, connect to an unsecured network, send data to a neighbor’s smart TV which is connected to Internet, Bluetooth or other to a phone