It was just by chance that I noticed his shoes this evening. We went shoe shopping immediately. Mind you, we walk to school every day which is partially through the frosty grassy playground. He never said a word. When I asked him how long the bottom has been missing from his shoe, he replied, "Awhile"
Then again, this is the same kid who wore his underwear all day long with the waist around the leg and the leg around the waist and said that nah, it wasn't that uncomfortable.
I'm going to have to add spot check the kid's wardrobe to the list now and then.