I think the answer has to be, simply never buy a TV that you wouldn't be completely satisfied with as a dumb HDMI display. Cos even if it's not abuse like this, eventually the built in functionality will break, or become too insecure to keep active on your network.
In fact it goes for just about any appliance these days: whether it's your fridge, microwave, dryer, doorbell or anything else, if it doesn't have a "dumb" offline mode where you are still completely happy with what it does, don't buy it.