Yup, I would just keep it up. Hopefully, the "game" stops being fun. If it was gettting really ridiculous, and beginning to become a disturbance, then I would make sure that there was as little as possible for her to play around with. If necessary; I would remove the playpen sheet, attach velcro to the bottom of the playpen and it's mat, take off her socks before bed and ensure that she has NOTHING to mess with (nothing within arms reach of the playpen).