Now that Jessica Alba has fully immersed herself in motherhood and the business she launched related therein, you simply won't find her showing off much in public anymore. Not that she was exactly an exhibitionist before, but now she's got a couple million moms trusting her mommy opinion on products and services and she has to be a little more stately in her appearance. I know, I cried too when I first realized this new status quo for Jessica.
Nevertheless, you can run, but you can't hide the headlights just dying to be noticed for the paparazzi cameras on a big trip to New York. It's not the least bit cold in the Big Apple so I'm going to assume Jessica's nipples were just excited to be out on the town, in the big city, reaching toward the Empire State building and other altitude attractions with zeal and fervor. Jessica may never let them out to play in public, but out they will come nonetheless. Free the nipple -- or they shall free themselves! Enjoy.