What is the point of the flyer?
Someone said that the point is to get people to be cognizant of what they are throwing away, and that some people might search their trash for nefarious reasons. If that's the point, why not just put a flyer on there that says, "Hi. We're nice people, and we wanted to know that your trashcan is out here for all to see. If someone wanted to look through it, they could have. Are you sure that they wouldn't have found any personal information? Thanks!"
Why go to all the trouble of lying (you said you went through their trash looking for suspicious stuff - did you?) and pretending that you are some government agency? In one post, you even said that you used thicker paper to seem more governmental. Why go to those lengths to make such a material misrepresentation of yourself? And, why not be proud of who you are and what you are doing, if you really are trying to help people?