To answer your questions Fly:
When a consumer buys a product at the store, the list of ingredients is readily available. Not so at a restaurant.
More importantly, though...this kind of legislation has already raised awareness...not only in NY but also on this message board. Yea, banning them from restaurants does nothing to the processed stuff in the stores directly, but it's a step in the process to ban them from everything we eat.
For example...Frito Lay has eliminated all trans fats. Kraft has eliminated most trans fats...do your Doritos taste like $h! because of it? Nope...
Why did Kraft start eliminating them? Because they were sued over Oreos and the Oreo Challenge they used to market in schools. Kraft settled the suit and vowed to eliminate trans fats from Oreos and begin to eliminate them from the rest of the lineup as part of the terms of the settlement.
All of these measures are steps. If NYC and Chicago ban trans fats, that will give great momentum to the ball that's started rolling against trans fats in general. The processed food industry will be next.
Also, one more thing to note...this isn't just an argument against fat in general. Fat is most definitely part of a diet, in moderation, because you NEED some fat to survive. The problem with trans fats is that they settle around the abdomen and heart (around all the vital organs), they specifically raise the bad cholesterol and lower the good cholesterol. These fats are synthetic (except in some dairy products, where they occur naturally in extremely small amounts), and they are particularly unhealthy.
In making the change to a non-trans fat ingredient, the product will likely have about the same overall nutritional information, but the fat component will be far less unhealthy of a fat component.