I've been doing the same; get an AppleTV or GoogleTV dongle and never, ever attach the LG or Samshung TV to the network.
Benefits of this strategy:
* So simple, even non-savvy folks can follow the rule
* Protects your privacy
* Eliminates an unnecessary, highly invasive, and parasitic advertising vector (ads directly from LG or Samsung)
* Protects your TV performance and functionality from surprise degradation due to "updates"
I don't see any significant downsides compared to the upsides :)
It's unfortunate the manufacturers are in a position where such perverse anti-customer incentives exist.
All we really need and want is a great product crafted with love. What we got was a creepy spy box that eventually gets so slow it becomes unusable and worthless e-waste.