Worker reprimanded when their coworker who was supposed to cover their shift no-shows: 'I got in trouble for it'

In jobs and industries that operate off of shift work "The Schedule" is hailed by management as an ancient relic of extreme importance—and not as if it's a document they threw together at the end of last week, days after it was supposed to be posted. 

No, there wasn't a lot of thought or effort that went into drafting that schedule, but there sure as heck is a lot of thought and effort put in to make sure you and your coworkers keep to it… Since making this schedule is part of the manager's job, you'd probably expect that it would also be their job to find coverage for it when workers can't make a shift or call out sick. Yet, somehow, nearly every shift manager sees fit to force the workers themselves to call around and find coverage.

As a rule of thumb, once you've traded a shift with another worker, or they've agreed to otherwise cover that shift, that shift is no longer yours and no longer your responsibility. Still, there will inevitably be some murky situations where the coworker who was supposed to cover the shift forgets about it and claims that it was not, in fact, their responsibility, leaving a disgruntled manager who displaces their wrath onto the original shift owner.

That's basically what's happening in this thread, which was originally posted to a popular online workplace community. This young worker traded their shift with a coworker who no-showed to the shift, landing them in hot water with their manager.