Hmm, I wonder if its like some other games and its disabled in consoles because I haven't seen leaning in any videos other than the ones posted a year ago of Container City as well.
Edit: Questions such as this are best asked on the Splash Damage Forums.
More of a chance to get an official response.
Only leaning I could find was, like Napalm said, back in http://www.gametrailers.com/video/container-city-brink/59709 at
2:09 when Paul was leaning around the corner right after placing a charge at the door.
*I say Paul because he kept saying "I" thru the whole thing*But like the others already said, no reason to take it out and no mention of it being taken out so I would assume that its still in the game. Just funny that the peeps in the videos dont ever use it... wonder why?