@polycell public punishments are still messed up (particularly if its one grounded in the use of shame, used by a parent), I agree with
@suppebargeld.
I don't quite get why they are so adamant against just indulging her wishes and having fun with some cosplay. The store was closed anyway, and they were still getting paid. Besides, wouldn't it be fun to try out such outfits some day? Particularly if it is made using proper textiles? Also, the story is based on them liking eachother, so they would probably do it just so they can get to see the other one do it too.