I understand the policeman’s motivations, but the idea that the answer to abusive scammers is that we should reduce our level of trust in society generally is severely damaging.
When you're in a suburb, a stranger directly outside your house for any amount of time is far less likely to be a friendly just going about their day,
like it would be in a small town or in a city.
Learned reactions. Ugly overreactions, often. But, learned.
I don't answer the phone or the door unless I know someone is coming or I'm expecting a parcel. And I have a huge 6 D cell flashlight by my bed (that I will not hesitate to use as a weapon)
Granted I don't live in a suburb but in an inner city in Europe.