Biblical view of survivalist and preppers

What do you think of Christians who adopt a "survivalist/off-the-grid" mentality? Who sell their homes, move to remote desert or mountain locations, stockpile food, grow their own crops, live like "pioneers," and strive to be as independent of the "system" as possible? I know several people who are moving in this direction. I don't completely disapprove-after all, I'm sure we'd all be better off if we eliminated some of our modern luxuries and learned to live more simply. Still, I can't help wondering if this is really the way God wants us to behave as His witnesses in the world. What do you think?