Even a dedicated subnet won't be enough, because these devices could be made to connect to any open wifi until they can phone home or even use the cell network,

Even a dedicated subnet won't be enough, because these devices could be made to connect to any open wifi until they can phone home or even use the cell network, without the user even knowing about it. > I guess, at this point, the other commenter's solution of "just stop using those things" may be the best. Yeah. Assuming this doesn't change, this is the end result for me, at least.