Saw this on the Bloomingdale listserv and thought it worth passing on:
Neighbors, someone is going through the Bloomingdale/LeDroit Park neighborhoods placing a small “sorry we missed you” notice on doors. Please be cautious in this matter. It has been reported in other neighborhoods as a tactic to determine if someone is home for later break-in. Should you see this notice on a neighbor’s door and they are out of town, if you are able to contact them, please ask if you can remove this “notice”. Please check on your home-bound neighbors to help avoid possible home invasions.