I work for a large library system in Canada as a Public Service Assistant (I'm those people behind the front desk who help you find that book about dinosaurs you've been wanting to read).
I was working the front desk today when my Supervisor (one tier right below the Branch Head) pulled me into the staff workroom. Supervisor is in charge of making sure all our staffing hours work with each other (no gaps in the staffing schedule, etc.), then Branch Head signs off on it. Supervisor mentioned that Branch Head scheduled me to work extra hours from 12:30 to 8:30 on the 13th.
Supervisor: “Did she ask you to work these hours?”
Me: “No, she never asked if I could work those hours.”
“Are you able to work those hours?”
“No, sorry, I won't be able to.”
“Oh okay, I will remove where it says you will work extra hours.”
Let me paint for you how unorthodox this is. Our union terms about extra hours are that we must first agree to work extra hours before we are scheduled to work them. It's pretty hard to agree to work extra hours if you're never even asked to in the first place. The only 2 ways we work extra hours are if we specifically ask/get asked to work more hours, or if we formally apply to receive monthly extra hours offers from other branches within the library system.
I don't know if my branch head and supervisor have some weird arrangement of “schedule first, ask later”, but had it not been for my amazing supervisor, I would have gotten a phone call asking why I wasn't at work working a shift I never agreed to.