Well this should not be considered the most reliable study, performed by the makers of Honest Tea. Check out the results.
Given that the tea stands were set up in busy locations of major cities we can presume that the study was less about how honest the people are, and more related to their sense of community judgement. So what does it say about the bottom of the list, NYC, and their views of being judged by their peers? Or just a general feeling of protection to break the law in that city?