> I simply tell them I'm going hiking in $NationalPark where phone service is not possible.

That's how I got married = "I was told that if you take one of the trails from the lodge over to a high overlook your phone will report signal for at least one carrier from down in the valley, but they're not sure if anyone's ever actually managed to make a call."

Sequoia might not be that isolated these days, but it was still a great choice.