Nobody was in any danger. A bee swam looking for a new place to hive, with no honey to protect, won’t sting people.
See bee bearding contests.
They will sting if you are rough with them.
Ask me how I know.
Understand that I'm not saying you can hold a baseball game around them, and that it wasn't absolutely necessary to remove/relocate them -- it was -- I'm just pointing out that a honeybee swarm is in no way comparable to a swarm of, say, wasps or hornets which is a true danger. I'm just pointing out the distinction that I didn't see covered in the article (maybe I missed it as I'm still on my first cup out here this early morning).