Aside from “don’t show your ass to the police in public,” there seems to me to be another lesson to be learned from the Cambridge Incident:  make sure your neighbors know you. 

Now you don’t have to go over and spend a lot of time with your neighbors, but it certainly helps if they at least know you by sight, if not by name.  It would have saved everyone a lot of grief if the neighbor who spotted Professor Gates breaking into his house knew that it was him, and not some random thief.  If I were to have to break into my house at some point, I know that at least the neighbors around me know that I belong here.  And if I saw one of my neighbors trying to get in through a window, I’d probably go over and see if I could help somehow.  But it sounds like in Professor Gates’ neighborhood no one knows anyone else, which is truly unfortunate.