Most people never looked up. And, if they had, they would not have seen anything, save for a slight movement of black against black, drifting across the urban darkness. Crime Alley wasn't exceptionally well lit, even by Gotham standards, and it was a dark, cloudy night, moon and stars both obscured. It was also bitterly cold; Selina, even encased in her leather suit with all of its fine gadgetry, was shivering a little.
She was also the kind of woman who looked upwards––which was easier, as she was sitting on a rooftop herself, taking stock of the situation. And where most people would have seen nothing but the black shadow drifting across the sky, Selina was wearing infrared goggles.
Even so, it was hard to see the shape that moved across the sky. Probably, he had some kind of insulation to make it harder to spot him. If she had not been looking up (assessing, really, the feasibility of scaling that large building where a certain drug lord had his headquarters; how fast she could ascend, which window she could break into), she would not have noticed the Batman at all. And what is he doing out here?
They always said that curiosity killed the cat; Selina rose from her crouch, and ran, with light steps, across the roof she was on. It was a simple matter to climb up the side of the next building––windows, loose bricks were handholds, and the fire escape made it almost a laughably easy ascent to finish––until she stood on the same rooftop as Gotham's most famous caped crusader. "Isn't it a little cold for bats to be out tonight?"