I hate when people steal my days off. Granted I don't work now so all my days are days off, but back when I did work I hated it. Next time they announce that they will show up at a certain time, what if you just aren't home? Take Claire out for a walk on Sunday or something? Or call them back and say "Sorry, Sunday doesn't work for me, how about Saturday?"
Or, you're going to smack me when you see me this afternoon, but what if you traded your Saturday and Sunday activities, and instead made Sunday your social day and Saturday your relaxing day? I know, I know, I'm really going crazy here. But technically it is an option.