As a hobbyist photographer I once went on a street photography course in London.
They did cover the ethics and morals of street photography, along with various techniques about what to do if challenged.
UK law is a bit different than US law. From my understanding the US law allows any photography in a public space. While UK law does not allow street photography on private property (although if you're on public property photographing into private property that's OK), plus any photos of places where they'd expect a degree of privacy. So you can't stick your camera over walls etc.
I also checked the laws around photography in the UK and there are general rules around nuisance photography (that wouldn't cover conventional street photography). Additionally I looked at rules around photographing children in the UK, and generally it's not permitted to take photos of other people's children without their parent's / guardians permission.
The photo on the subway in the article wouldn't _technically_ be allowed in the UK, as the tube in London is private property (although everyone takes photos there) and photographing other people's children without permission isn't really allowed.
At the other end of the spectrum, I've also been to events on private property in the UK like Comic Cons. They have a very comprehensive photo policy for both the photographers and the attendees. While photographing at these events I often switch to a kind of "pantomime" mode, where it's very clear that I'm taking a photo and the subject has clearly agreed to be photographed. Other times I point my camera lens downwards when checking the shots and show them to the subject or have the lens cap on. At these events I've spoken to cosplayers who have thanked me for working like this, as they have had trouble with photographers behaving inappropriately.
I've only been challenged twice while doing street photography. Once while on the street photography course where I was taking a photo of a sandwich shop and a guy walked out while I was taking the photo. He politely challenged me and explained he was uncomfortable with me taking his photo. I showed him the photo and explained he wasn't in the shot. The second time I was challenged more aggressively, I was taking a photo of a long street with trams on near a tram station. Someone came up to me almost shouting asking if I took their photo. I explained I was taking a photo of the tram lines, and showed them a few shots. They seemed happier after that and left me to it. In truth when I got home and looked at my photos they were in the shot, but they were just one of many faces in the crowd. This shot was all about the lines of the tram station and how busy it was.