I have previously been too nice and pick up shifts to help my manager out when there's no staff available for the saturday evening shifts. This time I offered to be on standby but he put me on for a shift anyway. I let him know that I couldn't do it any longer because I have to get up early the next day for another job. He explained that it works is that even though we're casual staff, we have to commit to the shifts that we're assigned to and asked if I would like to finish earlier. I haven't replied to him yet but surely as casual staff you're not obliged to work shifts with enough notice? Do I still have to work the shifts?