I had a few days off with the flu recently an was actually called to come in as a morning shift to be relief for the night shift that I was actually sick for.
There was even a recent instance of someone getting stood down due to a naughty type thing then stood up then sent home early to be able to come back 8 hours later to cover an unfillable night shift. It may be $65 an hour for normal time but when you never get days off you can't spend it.