This from Chapel Hill Police:

Suspicious Individuals Going Door-to Door

The Chapel Hill Police Department is investigating numerous reports of individuals going door to door representing themselves as workers of a construction company doing work in the neighborhood. The subjects are reported as being well dressed and polite when speaking with homeowners. The subjects have told residents that they are making notification of scheduled work so homeowners will not think it’s suspicious and call the police.

Should you encounter anyone going door to door we recommend the following:
• Do not allow the subjects to enter you house.
• Notify Police immediately by calling 911.
• Attempt to get a description of the individuals (Race, Sex, Age, Clothing)
• Get a vehicle description and license plate number if possible.
• Note where you last saw the subjects and which way they were traveling.