It looked for all the world a happy accident courtesy of the photographer's flash bulb.
Apart from this particular pic, where she's staring down the lens and giving it the big sexy.
So yeah, gonna have to assume that everyone was briefed well in advance about how she'd be walking from a building to a cab without a bra on. We have, once again, been had.
Though on the bright side; them boobs! Speaking of...
Nice.