Some brands have TVs share Wi-Fi with each other, so even if you don't connect it to Wi-Fi, your neighbour's TV will silently share with yours.

Which? All I've seen over the years is people repeating the same rumor.

This is an assumption that since Amazon Sidewalk exists, smart TVs must have something similar. There's no proof, and I think if it were happening without being documented it would be a huge scandal.