here is a copy of the post i made in the personal security stickie.
I would make a suggestion. While blending in with the crowd or walking down the sidewalk, Look everyone you can in the eye. It shows that you are alert, attentive, and confident. These things make you a less attractive victim, hopefully negating any need to go condition red in the first place.
Being in a wheelchair I am an attractive target to begin with, I work in a high crime area, and close alone after dark sometimes. When I roll out the door and lock the door, my head is on a swivel (spellcheck save me). Anyone in the parking lot or walking down the street gets a smile, direct eye contact, and a nod. Normally the homeless around here get a head swivel and a not today stare.
Set comfort zones around you. <30 feet get lots of attention, <60feet get acknowlagement. Don't just look, Most people in condition yellow focus only on their vision. If you focus with your ears as well you get an added buffer. Heavy footsteps get extra attention, running even more. And remember not all BGs are Human. I listen for dogs running as well. (its a problem in this area).