Anonymity: Friendster in the Physical World

Weekend before last I went to a party, the host of which is so far removed from me it hardly worth describing (I'll try-- a friend of my friend's roommate). I headed for the bathroom and saw this very pretty and distictive-looking black girl I immediately recognized from the subway. I couldn't place when or where, but I knew I'd seen her. I was, luckily, enough beers into the night to start doing things for their story-value. So I walked by, stopped and told her I recognized her from the train. She looked at me, paused, and admitted she recognized me, too. Then she said, "You must live around me, you got off at Franklin." Some small talk ensued, mostly about how I don't actually live there, hey look we have the same shoes, mine are from DSW, yours too? And I went to the bathroom. And then I had time to think-- how incredible! I walk around all of the time looking at people and always kind of assuming they're not looking at me. Frankly it's not totally shocking she recognized me-- since probably any white girl getting off at Franklin is more noticeable than even the most striking black girl-- but still. There is this feeling of anonymity in New York that can be total horseshit. If you walk down 7th Avenue in Park Slope picking your nose, this will trump any kind of brilliant comments you made in Anthropology of African Americans in the minds of a frightening number of Wesleyan alums.
But it's always kind of eerie, being told that someone saw you somewhere when you were totally unaware. Anyway, this little parable fits nicely within the Friendster situation-- learning that randies look at me as I look at randies is kind of reassuring/makes one feel less crazy or like some kind of gossip/information whore. But PLEASE this should only go one way. Ridiculous as it may be and possibly impossible, I'll say it clearly, I WANT TO SEE WHO LOOKS AT ME AND NO WAY IN HELL DO I WANT OTHERS TO SEE WHO I LOOK AT. If we could work something similar out in the physical world (like if no one could see you when inappropriately ogling someone's deformity) that would be great, too.