It can be, sure.
Hell, even without laws or humanity, pursuit is a hallmark of predators, it's what they do to prey.
It's also not an uncommon thing we experience, see on TV, etc., that occurs prior to being robbed, mugged, raped, etc.
I bet a number of travel and anti-rape guidlines involve being on the lookout for people tailing you, esp. alone, in the dark. Good lord, seeing otherwise reasonable people flip-out on this and start to actually claim that following is not aggressive because they "feel" a particular way about the Zimerman case, is awful.
I have seen in the home-defense type threads similar individuals who claim that the simple act of having both feet just past their property line, is sufficient justificaiton to kill the person. But following someone at night...nah, business as usual? Mind-boggling.