AC Becasue well...
Phones have never really been switched off.
I was in a certain briefing where we were told how even an "off" mobile phone can be used as a listening device remotely.
The mitigations suggested were... don't take a mobile anywhere you might object to someone else listening or yank the battery if you do. Of course, these days, yanking the battery is, mostly, not an option.
This was 20 odd years ago. I have no reason to suspect those providing the brief had any reason to dissemble about the facts.
Biting the hand that feeds IT
