Yeah, the AI can do weird things sometimes. Tonight, a civilian spotted me (first stage), and a bunch of guys appeared. I ducked into a shadow, but one noticed me. He walked over to me with his gun drawn, and I drew mine. We then had a staring contest for a good five minutes (I was trying to win without killing). When it became clear that he wasn't going to leave or shoot, I decided to shoot him in the face. Another guard noticed that his pal had died mysteriously, and came over to investigate (after calling a few more of his friends). Well, three guards walked past me and the dead body (the body was in plain sight), then decided that "it was nothing" that killed their friend.
But it is a great game.