It all depends on the lighting, the size of the crack and how attentive you are while pooping.
>From what I have heard, it is best if the
stalls are located in a section away from
the urinals. This way men who want to pee
and flee can do so undisturbed.
As for the size of the crack, the old wood stalls at the George Washington Bridge Bus Station were quite generous in this regard. The layout was also quite conducive. When you entered the men's room you walked straight ahead to the urinals while the stalls were at a right angle to them.
I am unfamiliar with the layout of the men's room in question, but with heavy use quite a crack can develop. If a police officer were intent on doing his job well, I am not surprised that he should be able to see the color of a peeper's eyes.
One more thing: I jest about academia, but below is a link to a paper given at an academic conference on cruising tea rooms.
http://www.allacademic.com/meta/p107467_index.html
More info here for those who are interested:
http://www.planetout.com/news/history/archive/10251999.html
Brian