It is interesting that you rule out retirees for dish washing. Then what have i been seeing in coffeeshops or hawker centres? Were those dishwashers actually young people disguising themselves as old retirees? Must be la! Or can i say you talk cock?
If you need to ask me if the definition of lowly educated comprises of the realm of intellectually challenged, then you are clearly hopeless.
Coffeeshops and hawker centres use plastic plates which are light. Restaurants use mostly porcelain plates which are a lot heavier.