@Carrotghoul : My thoughts too.
I think it is about appreciating that no wo/man is an island.
So person A sets off, in the car, to travel to their 2nd home to visit.
It's not "essential", but they want a change of scene.
They have no intention of meeting anyone else, either en-route, or while there.
But they break down en-route, so have to call out breakdown services.
Enter, breakdown person, Mr B.
But, he can't fix it roadside, so has to tow them to nearest garage where mechanic C has a look.
Car needs a new part, which he can't get today, so now Ms A needs to book into hotel - checked in by receptionist D. etc etc
Or, road accident with Ambulance personnel, Nurses, Doctors etc have to be involved.
Any of these are as a result of an unnecessary journey in the first place.