Edit: it was Samsung, where Wi-Fi Direct was always-on, and concurrent with STA mode wifi, enabling other WiFi direct devices potentially to connect to the internet, including other Samsung televisions. Their televisions were also hacked to gain root over a standard DVB broadcast on fully patched firmware lol so it might be possible to pwn a whole city at a time through that vector.
Smart-TV platforms have long done cross-device identification, and there have been some surprisingly aggressive local-device discovery schemes.
In all, smart devices are pretty much surveillance devices, and a privacy nightmare. I have had enough exposure to shady goings on that I am nearly certain that most devices ship with intentional backdoors sold to three letter agencies or malware rings, either by unscrupulous engineers or by the company itself.
It’s just hard to pass on the payday that a wide deployment of a permanent relay/mic/camera/sniffer represents, especially if it’s likely to end up in corporate or industrial environments.
I’ve had speculative offers to compromise smaller projects, and I’m nobody. I have no doubt that engineers working on widely deployed projects and systems are given very attractive offers to provide tailored access.
So you have to go a step further and remove the Wi-Fi card, because there is no guarantee that someone else won't connect the TV to the Internet.
Like HP printers. Don’t give your money to companies doing shit things.
Vast majority won't know or care.
The way this gets fixed is laws not workarounds unfortunately.
This, unfortunately, is the biggest problem those of us care about privacy face, especially when trying to warn people about it.