I've come to the conclusion recently that a lot of people are just really, really trusting. They think that a car will definitely stop for them, so they walk without looking. It happens around here all of the time when I'm driving -- cars nosing into traffic when they do not have right away, turn across traffic when there's not enough room/time, etc., all blithely assuming that other cars will slam on their brakes to let them pass. Yesterday, I watched an SUV park itself across two lanes of traffic for an entire light cycle because it pulled into the street assuming someone in the long line of cars in the turning lane would make room for them.
When I was growing up, my dad taught me that it was my job to be aware of my surroundings and keep myself safe. Never, ever, ever count on another car to stop, slow down or actually turn when their turn signal is on. :-) It was good advice.