Lots of construction work is only safe to do when the crew is working together. [...] It's not just a union thing.
It's certainly a something thing. Here's a conversation I had with a construction worker in NY:
Me: Hi, how's it going.
Construction worker: I'm having my lunch [As in: Go away].
Me: Mind if I grab a seat? [There wasn't any other seating, this being the point of the attempted conversation]
Construction worker: CAN'T YOU SEE I'M HAVING MY LUNCH?
I just assumed it was some kind of union thing, they're being paid to eat but not anything else, so if I want to ask whether I can grab a seat I have to do it during paid work hours.