On this particular topic, basic software Freedom would be sufficient. But apparently enough people don't even care to make purchasing decisions based on anti-features. Or at the minimum, say hiring a technician to fix your brand new fridge as described in OP.
So, as seems to be the trend, most people are effectively content letting technology take away their agency. A small number of us can swim in the stream of navigating it so we don't get ruled over by it, but once you're doing all that work just to tread water it becomes awfully tempting to use your understanding to subjugate others.
Happy to be proven wrong, wouldn't a Faraday Cage need to be tuned to absorb whatever wavelength you're aiming to block?
In the same way that you can see in to a microwave because the terahertz μm waves can pass through the holes but the microwave mm waves are blocked.
Until it won't be legal to impair Big Brother watching you.
No reading my cards without actually taking them out.
It turns out I kinda have that already. My 1919 house has plastered walls, some of which have a wire mesh underlay. It blocks wifi signals between rooms beautifully.