Just a Reminder

One of my pet peeves is when somebody gives me a "reminder" when they never told me about it in the first place.

Oh, "remember" you're working tomorrow from 9-5.

Just a "Reminder!" There's a mandatory meeting on the 20th from 4-6pm.

Etc.

It's not a reminder if I was never told. It's a notice. Reminder implies there was a first notice. Which there wasn't.