It is an ouline, but it is NOT chalk. I can see the man's package. There was a movie a while back starring Arnold Schwartzenegger where he was in this futuristic world and everyone walked down this corridor and the security set on one side of the screen and people passed on the other side of the (wall) and they could see peoples skeletons and anything they were carrying. No need to slow everyone down. Now come on wouldn't it be nice if people just walked down a few corridors and were screened without even slowing down. No lines, no harrassment, no shoe removal, no dumb questions. But we have got to get to that point and it takes steps. Maybe this is just one of those steps.