When I lived in Hebden Bridge I got chatting to an 85 year old woman in my street. She was saying how sad it was that people felt that they had to lock their doors now. When she was growing up there neighbours used to just walk in whenever they felt like it to ask for a cup of sugar etc.
I found something similar as recently as 1980, just after I finished university and went to visit a friend who lived in a village in Devon. And people really didn't lock their doors - I didn't think such a thing still existed.
And they invited me to visit, from Liverpool... what were they thinking?!
And another occasion, I was on a long-haul flight back to the UK on Czech Airlines in 1990, just after the so-called Velvet Revolution, and the timings were perfect for me to stop over for a few days in Prague. My travel agent friend told me how to contact someone at the airport to arrange private accommodation (hotels were still scarce, and still the old communist edifices), and I stayed for four nights on the sofa at the flat of a lovely couple (who served me beer with breakfast!). There was no key, they didn't lock the door, even when they were both out at work all day.
It was a truly memorable time, but I couldn't help feeling saddened by my thought that they clearly didn't see the approaching tide.
(Oh, and to be slightly relevant, I was unable to find a bicycle for hire, which would have been perfect for getting round what was then a very laid-back city - I could have bought an old Soviet one, mind)