GM did show that the devices scan for open wifi networks, and users in the comments have claimed that it connects without their permission.
Gamers nexus did not make that claim about them actually connecting though.
I don't mean to be rude but it sounds like you just don't want to confront the rest of your household about taking the TV offline and are coming up with excuses to tell yourself this is actually fine.
You can even prepare for it by printing the details + qrcode beforehand.
Connecting to a wifi network is one of those things every terminally connected non tech savy people are able to do these days.
Not "my network has a default or empty password, I can't make people sign in again."
Also, some people have a lot of wifi connected devices, including stuff like light bulbs. (Again, not me.)