Lost or nicked? It happens. Ya get the rough-nut families trawl the schoolgrounds after hours sometimes. You can often tell because suddenly their kid is wearing new uniform with the tags inside the collar cut off
At a Special School I worked at in Melb one family gave me the shits. They never sent their kid in any spare clothes, so when they messed themselves we would send them home in spares. Not only would they never return them, but their kid would turn up at school weeks later actually wearing them
