to address this park thing you also have to address the culture of fear in parenting. To fill up the local parks again kids must be allowed to go out on their own and play in groups like they used to. This at present is labelled as bad parenting as 'you don't know who is out there'. My friend...
I am not sure about the need for a tax but getting the information out to the consumer is key. I like the idea of labelling with the teaspoon thingy. This way consumers can at least make an informed decision based on knowledge of the facts.