They DO hurt like heck. I stopped my ATV right over a nest and got stung several times. IT HURTS. Took care of the nest at sun down.
On occasion I could find their nest just by quietly standing and watching the field. Eventually, I would see some motion and focus on where they were coming from.
I have often thought that a YJ nest must have some odor that you could train a dog to find. Just a thought.
Foxes and skunks and such will sniff out dig them up to eat.
My sister was riding a horse one day in the woods and it schlonked a foot through the roof of an underground nest. She got off calmly and walked it away. She got stung 60-70 times (in a high cut T) and the horse about 200 (it was foaming at the mouth). She joked about it increasing her bust size about 3X for a few days...