As a New York City native and Certified Health and Wellness Coach, I've watched this whole issue of Mayor Bloomberg banning soda and other sugary drinks with great interest. I heard the first anti-New York City Sugary Drink Ban campaign ads on the radio when I visited New York last Summer and thought that it would be an interesting battle.
Newsflash--healthy habits happen when people are ready to make a change and choose to go with what's good for them, not when they're forced into it. And if you restrict what people can have, it also will tend to make them want to do the opposite and rebel against it.
On the other hand, regular soda and sugary beverages are definitely contributors to obesity and diabetes in adults and children. Children can't decide for themselves, but their parents sure can.
But the "ban" didn't limit getting 2-liter bottles from the supermarket or convenience store, and someone could just buy two drinks to make up for the smaller quantity. I think you would have seen a lot of businesses offering BOGOs for 16-ounce drinks and there goes the ban anyway.