The Sapienza computer scientists say Wi-Fi signals offer superior surveillance potential compared to cameras because they’re not affected by light conditions, can penetrate walls and other obstacles, and they’re more privacy-preserving than visual images.
[…] The Rome-based researchers who proposed WhoFi claim their technique makes accurate matches on the public NTU-Fi dataset up to 95.5 percent of the time when the deep neural network uses the transformer encoding architecture.
First of all: cardboard does NOT block electromagnetic waves. You need a Faraday Cage for that. And even then, it has to have holes of a certain size to block specific wavelengths/frequencies. It’s why you have a mesh on the door of your microwave for example.
Secondly: they’re not attempting to photograph you. Just identifying your unique signature once would allow them to track your location anywhere where they have the gear installed.
EDIT: I suppose your comment is written in a way that it’s not clear whether you’re saying certain frequencies absolutely require meshes of a certain size to be blocked or if you’re just adding that extra detail about the design of Faraday cages for the hell of it. But…
Original comment: It doesn’t have to have holes to block radiation. A continuous sheet blocks all frequencies. A mesh is just nice so we can see through the cage or allow air to pass etc.
From the page you linked: “A Faraday shield may be formed by a continuous covering of conductive material.” “… if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation.”
My bad, a Farady Shield works just as well and it doesn’t need holes. But I was thinking about ways to combat this while posting and a solution involving conductive fabric was going through my head during that moment.