[Billthedrill]

Walk “up”?

Well, of course! I hope you don't think that was faked. OK, yeah, the capes were hanging toward the building, but that was, uh, uh, rogue air currents. Yeah, that's it.

[Interesting Times]

As we can see here, Batman's cape quite properly hangs straight down toward the street. Robin's seems a bit more, ah, ambiguous.

Oddly, none of the photos available show the end of Batman's cape.