I dont know where in Kensington this meeting took place. I may be wrong, but not all areas of Kensington are coverned by ANY Eruv. The eruv from BP doesnt go all the way to Ocean Parkway and the flatbush eruc doesnt extend all the way down either. It IS possible that the person was actually in an area where there is no eruv, according to any opinion. Whether that should be the very first thing you say to someone you happen to meet, is another story.
Regarding Kensington, I dont live in the neighborhood, but the friends and relatives that I do know in the neighborhood are all very friendly people, in fact, some of the relationships were started by a conversation waiting for the pediatrician, waiting on line in a store, so yes, people from Kensington DO engage people they dont know in friendly conversation.