And a hilarious tip I heard about.....Wear a reflective vest. People will think your a surveyor, and take no intrest in you. This guy did it all the time.
It actually works, I have 2 reflective jacket for my old job. One of the thing i had to do is go take photos and check out the condition of the foreclosed houses, and that including the ones in the hood. If you don't want the drug dealer next door come out and shoot ya thinking you're taking photos of him, wear a big yellow jacket.