Actually, that was precisely it. I was in Times Square where there were tons and tons of cops, and not all that many revelers. (It was a really cold night, IIRC.) I heard the comment, looked around, realized they were cops and completely without thinking said, "You can't fucking ask that." Next thing, they asked for ID and as I began to reach for my wallet was thrown up against something by the three officers. It happened really, really quickly--just like being mugged.