If she is working to pay for her shopping habit she should be pleased to work stat days with the extra pay. Have a family "Christmas Day" on another day. If you are not religious it shouldn't matter on what day you celebrate.
Grant has been called out (and you get no warning) every Christmas Eve, Christmas Day, New Years and, come to think of it, pretty much every weekend this year, for the past few years now. This year we are going to his sister's at Okiwi Bay - no cell phone coverage :lol: