Thanks guys for sharing some of your experiences, those are some real classics. :)
The gentleman in our local bee club who's bee vac I borrowed for this occasion, hadn't quite gotten around to building my own yet, was telling me about a swarm call he went on when I was returning his vac late yesterday.
A woman called about a swarm, he and his buddy drove out to her location, she walked them to the back yard and pointed it out...A nice swarm of bees easily accessible on a bush. They turned around and went to there truck to grab their equipment. When they got back to the backyard, the woman said she was watching and they all just flew straight up and left.
Now that's a whole different kind of bummer....to confirm it's good, think you've got it, and it's gone! :(
He told me sometimes they'll do that and come right back to the same spot. Unfortunately, in this case they didn't.