What does Greg discover about his family's clothes at the laundromat? What does he do about this?

Greg finds his family's clean, wet laundry dumped on the ground of the laundromat, so someone else could put their laundry in the washer. Greg plans on waiting to see who did it, so he can dump their laundry on the ground. When he sees it is the chain saw-swinging wood carver, he decides to let it slide.