@Suzanne302
Well, you would think it was something you should automatically know how to do and, when I first started hosting, I thought some guests were just idiots. I mean, who leaves the front door open in London or any other big city?
However, I've since realised that, in their own homes, people operate on auto pilot a lot of the time. They don't come and go and think each time, "I am closing the front door." They just do it without thinking. The same could be said of turning off the lights when you go out or turning off the oven after you have finished using it, closing the fridge door, turning off a tap. I could go on and on.
When people are in an unfamiliar environment (especially when they have their holiday brains on), that 'autopilot' often seems to malfunction.
I don't want to leave notes up everywhere, nor to have to put obvious things like turning off taps in my already long house rules. However, leaving the front door open is clearly a major issue. So, I really do make a point of showing guests how to use the front door lock etc. even though it is REALLY simple. If someone leaves the door open, keeps leaving lights on, taps running or anything else like that, they will be reminded in a friendly manner not to do it and, usually, but not always, they do stop.
I get though why a host would put a sign on the door to remind guests to close it. I would consider doing that. The last time it happened was a few months ago. It was winter and very windy. I was wondering why there was such a draft coming from the hallway and, when I went to inspect, found the door wide open. I assumed someone had left it open that morning, only to discover that no one had been out of the house. In fact, a guest came home late the previous evening and was the last person in or out of the house so the front door had been open ALL NIGHT. I live in an urban area on a busy road. It was very lucky that nothing bad happened.