Scare tactic.
Work as directed.
Dont worry about it.
Easier said than done when management is gunning for you. I agree with what you're implying but it's so hard not to worry because management does some shady ass stuff. Add on top of that a not so great BA or steward and the idea of the union protecting you goes out the door.
OP, it's best to read the contract 10 times to get a good grasp on it and that way YOU know yourself what can get you fired or what management can and cannot do. When I was a rookie (still am I guess) I used to be intimidated by management. Then I read the contract a few times and gained a lot more confidence when dealing with management. Knowledge is power my friend.
If management ever says anything pertaining to production just say "I am doing the best I can do while being safe"