How would that work? "the wifi device will cause society to end, but the one in your house and in the Starbucks on the corner? Those are just fine." I doubt the type of people who would put these up are the kind of people to buy that line of reasoning.

I doubt that would make much difference. They still have to walk round and tell everyone to switch their laptops and phones off on planes even though they claim the plane will crash if you don't.

Probably because many people don't believe that anymore.. Last time i flew (in Europe) most people did turn off their cell phones etc.

Well, at least it seemed like they did.

I usually turn mine off, not because the plane will crash, but because it'll waste it's battery looking for a signal from a tower that it can't find. That's actually part of the reason that there's so much variation in cell phone battery life is that if you're in an area of lower reception it'll take more power to transmit back to the tower. If there's no towers to respond a lot of phones (used to anyway, can't confirm 100% if they still do) would try to transmit at maximum power to get a ping back from the tower and start getting a connection to the network.