Don't lie to your coworkers and tell them dribble like this. A coworker several years ago told me this and when I contacted the union (at the time) they told me she was wrong.
Maybe she's one of those type who is constantly putting in requests to be off certain days or asking to have her schedule switched after it's already been posted. I know people either need to be off or want to be off on a certain day, but with some people it's every single week.