As I've noted a couple of times on this site, Timnath officials agreed to allow Audubon members who are not town residents to bird the reservoir from the town park lands. If asked by a town official or volunteer, explain that you are birding. As far as I know that has always been sufficient. Above all, be polite and respectful of private property and don't take offense if someone asks if you are a town resident. We had to convince town officials to make an exception to their policy for birders and they can take away that exception at any time. If we all practice birding ethics we should be fine.