If you recall, there was a collection of all electronic devices, prior to the conclave.
They would have to have held a glass to the door.....
lasers on windows.
A laser beam aimed a wind pane would pick up the vibrations of the glass from far away...................
Electronic devices may have been collected from the participating Cardinals. No way others seeking to intercept communication would be affected. It’s like banning guns; only the law abiding observe the ban.
-—glass to the door. I bet our geniuses can read smoke signals too. And those Swiss guards wear those sharp looking leotards-—kind of strikes fear-——