I'm not joking, in my graduating class (long ass time ago now but still in the post 9/11 era) in order to call off sick on senior skip day they required a doctors note beforehand, otherwise you couldn't graduate.
Some kid puked on the floor in the hallway because, well, he was sick, but wanted to graduate. Based dude that he was he chose to stay even after they tried to send him home because "I need to graduate." He missed the bathroom a few more times that day. Absolute fucking legend. I don't think it changed anything except for completely ruining the cleaning staff's day, but when you're that age and you've got a message to send you send it how you can.