In this case you could couch the subject using specific known events like power outages, and being snowed in for a couple of days. A week with no power & no heat can change your perspective. Beyond that they probably need to discover their own frailty.
You might help them with the idea they have about isolation equating to safety. A low crime rate is not the same as no crime, and being alone where no one can see or hear you does not make you safer. I’m sure you could find a diplomatic way to explain to them reality.