Neither would have done a complete job alone, so under the circumstances, your guess was as good as anyone's. You are kind to be embarrassed on behalf of a waiter who doesn't even know that a used utensil should be replaced and not returned, but he may have been acting on orders from the management to save dishwater. Miss Manners wouldn't put it past an establishment that serves food that cannot be eaten gracefully. Instead of holding their applause until the names of all the graduates have been called, various levels of applause and cheering are given to each graduate. Non-graduating students stand in small groups to cheer as their friends' names are called, with parents and other adults also taking part.
Some people actually bring plastic horns and cow bells to make noise.
A number of graduates receive no applause at all. Although this might mean that their friends and family know how to behave at a graduation, it gives the impression that they are friendless. I have a child graduating from each of these schools, and I would like to know how I should respond as my children's names are called. What you and Miss Manners have observed is something similar to the old school Valentine's Day, where the names of those receiving Valentines were called out as each card was taken from a box, thus focusing every one's attention on who was popular and who was not. Eventually, schools abolished this custom.