One of my students asked about a situation she'd recently faced while running on a local trail. A guy on a bike seemed to be pacing her, trying to chat with her. The really chilling question she remembered was him asking where her car was parked. ???? Why was he interested, she thought, can't be good. She told him a parking lot a bit further up, where there would be more people (and where her car was NOT parked). He rode off. As she ran past the lot she could see him there, waiting. She left him waiting and went on (apparently he didn't see her go by, or he didn't follow).
The class brainstormed other options, just in case. One woman suggested that she tell every other runner and jogger she meets something like "hey, did you see that guy on the bicycle? The one asking women where they've parked their car, and then waits for them. Really creepy! Spread the word." Soon you can get a buzz going, and people will actively be on the lookout for the guy. This is a GREAT suggestion, as it gets people more aware as well as looking out for each other.