I can think of two incidences of stranger danger.
(1) I was vacationing in Florida with my family, and I ended up bumping into some random guy at the beach who asked my name. I gave it to him, he gave me his, and I moved on. But, as he was leaving the beach, he caught me alone and asked if he could have my number. I told him no, but he insisted on giving me his number. But, he didn't have a pen or paper on him, so he asked if I would go back to his car with him! Which I told him no. So he insisted that he tell me his number and I repeat it back to him until I had it memorized!
My cousin saw the guy, but she didn't come rescue me because she wasn't sure I wanted to be saved!
(2) Maggie came back our room in BG, talking about this guy who had been muttering angrily under his breath behind her the whole way, and she was certain he was going to try to kill her or someone or something. But from her description of the guy, I recognized him as someone from one of my classes who was known for having "oddities." So I talked to him in class the next day, and said, "I talk to myself when I'm angry or upset about something because it helps me think things through. I'll have to be more careful when I'm out and public. I didn't realize I looked like a murderous madman."
EDIT: Sorry, I meant to publish this tomorrow, and I forgot to hit the "schedule" button!