There are no ultimate ethics in street photography— you just dictate your own code of ethics for yourself.
Shooting photos at the expense of others
Is it possible to shoot photos without upsetting others or at the expense of others? I don’t think so.
The truth is:
It doesn’t matter if you shoot photos with or without permission— there is always a chance that your subject won’t like being photographed, they might not the photo you shoot of them, or they might not like you sharing the photo.
I believe that street photography is artwork that requires you to use other people (strangers). The whole process of street photography is risky— you risk upsetting others, you risk physical or mental attacks from your subjects; but this is what makes street photography interesting and enjoyable. Because street photography is so hard, it makes us street photographers more unique and special. Not everyone can shoot street photography — we should pride ourselves on the difficulty and danger of our artistic expression.