Hello,
Nice thread. I'm new to photography too, and I don't feel very comfortable going out with my camera in places nearby my house. I agree that when it is in touristic place with a lot of people holding cameras it is much easier.
I'll try to find out the rules here in Brazil, so that I don't run into big problems in the future.
But, if you think is easier to get when you see someone, whom is nice to capture.
*Take the photo first, go show it to the picture, ask for permission and saying that you're sending it also for him/her via email later.
** Asking permission first and shooting later?
Another social issue is that when you are in group and go to a nice place, such as a urban park, and start taking photos of things it can be very impolite. It's hard, at least for me who is a begginer in photography, to thinking in composition and pay attention to the conversation at the same time