As Tom Scott points out in the video you're just moving the problem. They may not be connected to the Internet, but surely someone has programmed them. Who? And

As Tom Scott points out in the video you're just moving the problem. They may not be connected to the Internet, but surely someone has programmed them. Who? And how do you know noone has changed the software? If they've been programmed at one point they can be programmed again. It's Pandora's box.