One interesting thought I had about this experience is this. Normally, you want to place a swarm in a box and leave it at the location until dark, for all the foragers to return. Well, in this area, it really never gets dark because of all the lights from parking lots, buildings, etc... The bees are just bugs and they are drawn to the lights like other bugs. Could this had been a significantly larger swarm the day before, but lost most of the bees during the night? There is no brood to keep warm or no honey to protect, so I may have just caught the queen and her closest attendants.