Strange day

So this was the plan today:
Teach from 9 to 12.
Grocery shop
Prep class for the evening
Teach from 6 to 10

All good. Taught class, gave exam, bought groceries, prepped the class. But didn't teach, because the students voted a 3-day strike. The strike is from the 20th to the 22nd, so tonight's class should have been ok. But they apparently cancelled all classes. No idea why!