You see it a lot and you have probably encountered it yourself… You need to call off for your shift or schedule time off for whatever reason but your manager or boss or whatever tells you that you need to find someone to cover the shift for you.
First of all making the shift is probably not your job and your manager is being lazy by telling you to do it but more importantly: You should Never EVER work for free. Finding someone to fill your hours while you are not on the clock? Thats working for free. Dont do it.
Next time your manager tells you to fill your shift while your out sick you tell them straight up that you are off the clock and that you dont work for free. They might claim its some policy that you agreed to by working there but that doesnt fucking matter: off the clock means no work from you.
Never bend on this. Never work for free.