<p>I haven't been to Berkeley, but I learned some things when I visted Boston to check out Harvard and MIT. #1, never, ever respond to someone who comes up to you and says, "Don't be afraid, miss, I won't hurt you...this is an emergency." Right. If it was an emergency, he wouldn't be coming up to a lone teenage girl for help. The others have been covered here: don't make eye contact, people saying "I promise I'll buy food with it" generally won't, and don't talk back to the man standing on top of a trash can yelling about the doom of "the system."</p>