Wonder what will happen if you are noticed using Google Glass
Better not bring your birding binoculars anywhere close to schools, or you better bring your own lube too.
I'm not based in the US where the paranoia seems to be sky high. I'm in India and one doesn't face too much trouble with people as long as you don't appear to be photographing them discreetly.
In fact, if you are using a DSLR at public places in India, instead of threats it is more likely that you will get requests from people to click their photograph and email it to them if possible. If you are carrying a tripod they'll think you are a professional and you'll get good natured inquiries as to which organization you are working for and whether their picture will make it in a newspaper / magazine.
The only ever trouble that I faced in India was with .... well .... a European group on a beach in Goa who were concerned that they would be photographed while I was taking pictures of my daughters (who were also in the water). Anyhow, the situation got resolved when I called out the girls and introduced them to this group and we met for a beer afterwards.
The remaining trouble has come with monkeys who plague the subcontinent and cause much more problems than humans. The tripod comes in handy for scaring them off.