How easy is to do Street Photography by targeting unknown people?

Hi All,

Lately I am been thinking in improving my Street Photography, and so, I have read some articles and blog posts about it. One of the things that call my attention in these readings is the apparent ease one can photograph people in the "Street" generally without cause any bad repercussion. With bad repercussion, I mean confrontations with the subjects of the picture, uncomfortable or menacing attitudes/posture, or simply an escape attempt by the subject of our cameras.

This notion of ease caught my attention because it very far from the experience that I have in doing Street Photography! One perfect example was the attitude of the subject of the following photo:

The Law

Despite being a guard of a public museum, and at the distance I was shooting there was no way he could tell that I was photographing him and not the museum entrance, the man came straight at me with all his Law-Enforcing attitude as if I was committing a crime!

The fact is, I cannot believe that a great deal of people do not mind been photographed by a stranger and do not take action in any way that makes the photographer uncomfortable about what he is doing. Do to this my work generally deals with at distance photos, photos when in ceremonies where people are expecting to be a subject of pictures or when people are very distracted and not notice me:

Sunday Gathering

Portuguese Academic Ritual of Passing

Playing at Sea

So, I want to know your thoughts and your experience on this subject. I think that maybe the responses that we get for our subjects are dependent of the culture of the people/country, the dissemination and the number of practitioners of Street Photography on the area one works, and if this area is a touristic one or not. 

By thinking on my situation, I think that in Portugal people are not very receptive to be subjects of unknown photographers, possible due to the lack of Street Photographers. In my country, Photography is not really considered as an art and/or hobby but only a mean to record important personal events (travels, birthdays, important ceremonies, nights out with friends, etc...). So photograph one unknown subject is like an intrusion in their personal "sphere". In touristic zones, this is more diluted as people are more accustomed to people with cameras in hand. However, they are still expecting that the camera is focusing on some important landmark and not on people.

So, what can you say about this? :)