The shoes slip up my son's heel when he walks.  This seems to be a problem with this size range of Vans.  My daughter wears a size 2 and they have some padding around the ankle area which seems to keep the shoe from sliding on her heel.  The size 12 that we got for my son does not have this type of padding.  Not sure why they don't have the padding, but Vans should look at adding this padding to the smaller sizes.