If George Zimmerman was just trying to protect his neighborhood, he did a poor job of protecting Trayvon Martin, who lived in his neighborhood. How could he protect people if he did not know who they were? Why target Trayvon, who was not committing a crime?
I would have assumed that Zimmerman was up to no good if he were stalking me in the dark, with a gun.
Anytime you follow someone in the dark, like Zimmerman did, they will get spooked. Do this at your own risk!