For the last three years I've done a trapout where the bees went into a cinderblock foundation. The 24" high cinderblock is faced with mortared field stone. The bees got in where the masons left some voids. I told the homeowner what to do after I left, but that did not happen in years 1 & 2. Last year I took it upon myself to seal it up even though there were a handful of bees inside. I got a call from the homeowner yesterday. He says in the last two weeks a few bees have been coming and going at that same place. I came out to inspect today and saw a few bees behind the screening I put up, and a dozen or so trying to get into the crack in the wall. The exterior bee behavior looked like a swarm had stopped and left, leaving a few stragglers behind. But then, while I pondered, a real swarm arrived. It settled on the wall over the crack. (It has no interest in my swarm box that I put out as they landed.) Can any of you explain why a swarm would stop at a colony location that they cannot get into? Don't the scouts predetermine their destination? Do swarms arrive with the intention of robbing? Any advice welcome.