I don't think getting rid of Happy Meal toys will stop people taking their children to McDonalds or stop their children eating McDonalds ("Sunnyvale blogger said that once her child tasted fast food, it took years to coax her back to the healthful variety"). I think getting rid of McDonalds will stop people taking their children to McDonalds (and I'm all for that). I say that based on my experience working with those people.
Consider neighbourhoods where there are no grocery stores. The only choice people have is convenience store food that they have to purchase through a glass window or fast food. Banning Happy Meals is not going to stop people who grew up in that world from going to McDonalds or taking their kids there. And here, in Ithaca, there's no way my students would have stopped eating crappy fast food because their kids don't get a toy. One student used to put her 7 year old to bed at 5pm so she could be rid of him and then would make runs to fast food places throughout the evening. Even the "healthier" options at McDonalds are not going low enough in calories to be allowed to include a toy.
The legislation is aimed at an entirely different demographic and a demographic that should know better at that.
A far better option would be to legislate what can actually go into a meal that's marketed to children. We ban tobacco for underage kids, why not fast food? It's addictive and will kill you too. And the children who grow up eating meals with lower fat, salt and additive content will develop a taste for healthier foods.