After a meal a table is sometimes left a little dirty: crumbs, a sauce smear, a drink ring. Once the dishes are cleared, the busboy comes back with a rag and wipes it, and the mess fades as he goes. Servers with nothing else to do help. Nobody is seated at a dirty table.
Places are now set by hand. The busboy takes silverware from the tray by the service counter, carries it over and sets each seat with a napkin, a fork, a knife and a spoon. Before, the silverware simply appeared. (picture: wiping, then setting)
An empty place shows a folded napkin instead of a plate; the plate comes with the food.
On Easy tables are never dirty and set themselves. On Medium they're left dirty about half as often as on Hard.
Over 10 test seeds a quarter-hour serves 49.5 guests instead of 52.5: the busboy and servers now spend time wiping and setting, and a table waits to be wiped before it's seated.