I just got almost pickpocketted!

Coming out of the subway tonight, I saw a loiterer, inside the entrance, just watching us few people coming home, exit the subway entrance. When I was coming up the stairs onto West 4th Street, I sensed something tugging at my backpack, so I turned around, and saw the same loiterer all up in my space! So I said "Hey, woah". He responded "Sorry, my elbow mustve brushed your bag" To which I said "It was still weird, sir, " (because I knew there was no elbow involved, just an unzipping sound) He threw his hands up in the air as if I had no right to feel weirded out, and I said "Way to be a jerk". He took off down the street, and I turned onto my avenue, whereupon I discovered my backpack was almost completely unzipped! My planner and stuff were all hanging out, and it was just a bunch of papers, nothing this man wouldve really wanted. But I was so upset and annoyed. He'd missed my important pocket with cellphone, wallet, ipod, etc. And there were other people around, so he wouldn't have been able to be too aggressive. But yea. just thought I'd share my almost mugging, since I'm still a little worked up. Glad I yelled at him. That's all.