Most people with a smart phone wouldn’t know any number to call since it’s not programmed as “carl” or “dad” even if they could find a land line. Bet they don’t even know the number for information.
I think the key is citizen band. Everyone should have a CB app on their phone. :-)
lol...
Get Zello. It’s free and you can create a channel for your family.
If you lose wi-fi and cell data it won’t work though.