I live across the street from a major University and every time I sit in the Subway sandwich shop below my apartment  these tall coeds seem to have some fascination about staring at me. I encounter coeds all day long and they will either just smile or ignore me , but for some reason that's freaking me out in the past month there has been two talls young girls that seem to not be able to get out the door without constantly turning their heads backwards as they're walking out the door and staring at me. Normally I'm feeling pretty confident , but this is freaking me.

Maybe just try a smile and a wave to break the ice.  I suppose it couldn't hurt to appear friendly and approachable.

probably a good idea

I agree with Christine.  Go over and say hi.  If you're willing to talk to them, maybe you can educate them.  The more allies the better.

that would be a challenge