I was wondering the same thing, normally I don't let anything sneak up on me but nothing woke up and then boom, this morning I have shoes I think are too expensive for feet and might fall apart if I walk too much in them.
I guess if whoever it is wants us to go to this party and they didn't think to give us a store to shop in, the least they can do is give us things to wear for it. But I don't know how they know what size shoes I wear but not that I would never pick these out for me.