It does when you are in reverse, but you have to push a button when you are pulling into the parking space. It's on the row of buttons down low, along with DSC, rear hatch, etc. Not impossible to find, but I usually have to glance at it to ensure my finger hits the right one.

My wife's Lexus has a switch to leave the parking sensors on all the time, but it is only the beeping with no display. It would be cool if BMW could provide an automatic option, where the display came on when the sensors detected something.