I made a friend at my last job (Stryker / Abrams HQ) that was a janitor (cleaner), along with some of his friends who did maintenance (mostly A/C and boilers), all union.
Naturally, all the "blue-collar" guys in the prototype shop, especially the "high bay" driver-mechanics  were all union with the big one: UAW (United Auto Workers).
Whenever the UAW agreements were up for renegotiation, the others quickly followed. Thankfully I never had to cross their picket line, because without contracts us engineers had zero solidarity  lest we be shown the door, and management remind us of this every time.
Janitor Friend kept me in the loop the last time this happened before I left for good. His union had been protecting bad apples and company management knew it. The union could have everything they wanted THIS time, but they were warned that the next time there would be no negotiation -- the contract would be finished and all the union janitors would be let go for cheaper non-union, probably outsourced to a cleaning company.
I've been at my new job 3 years now, so I'm sure the trigger has been pulled on my friend, the Good Guy of the cleaning crew. It's sad that those with proper work ethic get burned by association.
1. Union driver-mechanics actually built and drove the prototype vehicles -- us engineers just got to occasionally direct them if we were nice about it. I learned some of their names eventually; they trusted me because I knew my $hit and didn't act arrogant about being a white-collar engineer.
2. Us engineers still got at least one tangible benefit: the unions around Detroit, UAW especially, still push for a full week of paid holiday between Christmas and New Year's Day -- owing to the strong Catholic Polish/Italian and Lutheran German local populations -- so naturally everyone in the company got it also. Without the shop, maintenance, janitors, etc. it wasn't worth it to stay open. (In this new job, I have to spend vacation time instead, but I get more of that to use; it's a wash.)