I've had people come to my home and stroll into my backyard for the city, looking over the open drainage ditches. This was legit, the guy had ID.
CITY HALL PHONE NUMBER:
Dunwoody trucks have magnets with the city logo and name of the department on them. If the truck isn't marked in some way, you might have a problem. If you don't see a truck, call City Hall (or the cops) and get confirmation that a crew is in the area. Call the police if you get one of these visits after hours.
ANYONE who comes to the door claiming to work for the city (or a utility, etc) should show you their ID on demand. No ID, no admittance, no exceptions. If s/he makes excuses or stalls or tries to give a reason not to show you ID, get on the horn to the police, ASAP.
LOCK YOUR DOOR. Always. Especially if someone is lurking outside. You can figure out that Thief #1 was telling Thief #2 in Spanish that the coast was clear and he could get in while keeping the couple busy.
If anyone is cruising around claiming to work for the City of Dunwoody, it's OK to call the cops. If the crew and their work are legitimate, there's no harm done. If they're crooks, they'll get busted that much faster.
Let's be careful out there, folks.