Saw a news segment last week where hackers were accessing audio and video of home baby monitors — when monitors were wifi based. Not only could the hackers see and hear what was going on in the room, they could speak to the people in the room.
I’m glad I’m boring.
It is not an unknown concept, and in fact in the past even cordless phones were easily listened in on. Any HF receiver could be tuned in to those frequencies if one wished and even radio scanners could access them.
Today, modern radio scanners are limited legally in the US to bypass the frequencies that cellphones transmit on, but the overseas models are not. Granted that is not the same as remotely turning on your cellphone cam and mic, but yes when you talk on a cellphone the conversation can be listened in on by anyone with sufficient knowledge and equipment. The transmissions are in the clear and not encrypted in any way.