Nice swarm but why would you use a bee vac on such a simple swarm to collect and put into a box?
Not sure "I" would have...As I said, I was just asked to tag along, it wasn't my call, or my bees. Honestly, the same question did cross my mind...However, I will say this in hindsight, it did seem to work quite well. He wanted to do it in one trip and didn't want to wait until after dark to leave. A minimal amount of bees went airborne and we hung around for a while vacuuming up the stragglers...I'd say we got virtually darn near all the bees present.
I'm not sure had he done a shake how many bees would have seattled and made it to the box in comparison. I'm also not sure what was his dead loss because of the use of the vacuum....but, he kept his suction very week and I wouldn't anticipate it to be much.
As I'm learning about swarms, it seems to be just like everything else in Beekeeping...Everyone has their own opinion on what's the "best" way to handle any given situation.