Yup. I turned mine on once on the plane to do my log books. It stays on for two hours before shutting itself off once you activated. It's also air integrated. After I finished, I put it away and didnt give much thought to it.
Until I had to go through the security checkpoint when changing planes...
They opened the bag to look in it. And here is this little oval device with an LCD screen that is beeping and flashing 5... 5... 5... 5... over and over.
Apparently the pressure change in the cabin made it think I was diving. (at a depth of 5')
And since it was an AI computer, with no air source hooked up, it was beeping like crazy thinking I had run out of air...
Needless to say, I was detained for a several minutes until they were able to determine that it wasnt any sort of explosive device.
And no, there was no way to turn it off.
So, I wont be doing log books on the plane anymore.