Pick a place within walking distance that will still be findable with the signs unlit: a school gate, a church step, a big tree you can describe. Pick a time convention, such as every even hour for fifteen minutes, so people are not standing there all night.

The house cannot be the only place because the house may be the reason you left. Fire, water on the floor, a road you cannot cross: any of those makes "go home" the instruction that fails. The second place should not depend on a lit sign or on a name you can only recover from a map on a phone.

Fifteen minutes, then leave, is what keeps the meeting from becoming a second hazard. Missing each other means the next even hour, not a search that wanders the neighborhood. Write the place and the rule where more than one person will see them, including a child who may not be holding your phone.

If the first choice can burn or flood with the rest of the block, name another, still close enough for the slowest person you are responsible for. Two places is not a complicated plan. One place that is also the hazard is a plan with a hole in it.

An out-of-town relative can be the voice-mail box of the family if any long-distance path survives. Give the kids the number on paper.

That relative needs the same card: the place, the time rule, the names. Otherwise they become a confident narrator of a plan you are not on. A number written down still works when the contact list is in a dead handset. A number that exists only as a first name in an app does not.

Practice the walk. You are checking distance, not patriotism. If the slowest person cannot do it without a struggle, the place is too far, and the even-hour rule will not save someone who did the loyal thing and started out anyway. Closer is the better plan.