Never connect your display to the internet is the classic advice.
Unfortunately some screens require you to connect to a Wi-Fi before they let you use them, causing you to need to create a unique burner hotspot on your mobile device to complete it. We've also heard of these kinds of devices connecting to any open network automatically too.
I can imagine from TVs and mobile devices these manufacturers have a database of Wi-Fi network + passwords it could use as well. Screens are also integrating docks into themselves meaning that Ethernet meant for your laptop or connected to your desktop could be used too.