Graduation response etiquette!?
Well, the proper thing to do would be to respond if they were or were not coming. Was this the actual ceremony or a party? We had many people that did not RSVP to my party, but then showed up anyway. Some sent checks and a card. The guest list for my ceremony was short due to a limited number of tickets, but everybody who was asked came to that. It is just good manners to acknowledge the invitation.