To begin with, I've made it a habit to scare the higher ups with open union and worker's rights threats. Nothing, not a single thing has been done, but it's good to keep them on their toes.

When in the break room with others, if a manager enters or steps in to se what's up, I will quickly pretend that we need to change subjects, something like "hey let's talk about the union later" or "Hey how's it going guys? Nothing much just talking about striking"

Well, now the big boss has gotten wind of this and does NOT find it funny one bit. I didn't outright tell them I was joking, but I assured them that if there really was a union or a union push, they'd know about it and wouldn't be finding out about it through break room jokes.