Bee’s relatives

There is a net of hornets in the soil at my work’s parking lot! As they are a protected species, there is protection put up for both, human and insects. A red and white striped barrier. Why not black and yellow?

I learned:
Honets are wasps. They have a very thin wasp waist (see images).
Hornets can use mouse holes and start digging larger parts underground. They are kind of aggressive, but I was lucky to get close enough for some pictures and not annoy them too much.
I learned not: Do only specific hornet species live in the soil?