Years ago.

IBM came out with a portable dictating machine. Before little tapes, this thing used a magnetic belt maybe 4 inches wide. Great machine. A couple of batteries and a folder of tapes and you could dictate your way across the country on a LGA to SFO flight, usually a Lockheed Super Constallation, prop of course.

Problem. The FAA banned radios on planes, did this by banning powering on any electronic device. 

Take out your IBM portable dictating machine and a stewardess would pounce. No more dictating during flight. Unhappy. Measured electromagnetic radiation from my IBM. Next to none. Complaints to FAA, IBM. IBM did battle with FAA, got an exception, send me a sticker to paste on the unit. Happy. 

Next flight cross country. Show stewardesses and pilots my sticker. Now middle of night, Have been dictating for several hours and bored. Sitting in the dark, cabin lights off. Idea. Pushed call bell. When stewardess came, I said that something interested me, "look out at that light in the distance. Every time I turn on my dictating machine, that light rotates about 30 degrees, just like the plane is turning, then when I shut off the machine, the lights rotates back to where it was. Here, look out the window and I'll do it for you."

In a flash the dictating machine was snatched out of my hand and she disappeared at a run toward the front of the [plane]. The boring night flight became interesting. I kept saying that if you will give me the machine back, I will demonstrate. Response was "NO!" I was given my dictating machine back when I exited the plane at LAX.

Before TSA.