@kwendy Good reminder. I didn't consider those gestures.
But I'll ask you, what is wrong with showing some humility during an award ceremony? It's pretty rare that the winner was pre-ordained and could have been no one else (and all their efforts are their own), and even then they are not gods. (Roman triumph ceremonies even had a guy hanging behind the awarded person whose sole job was to remind the winner that even with all what is going on, they still were not gods.)
tl/dr Maybe it's a very ceremonial "Thank you very much, Headmaster". (Doubling as a "I'm not going to try to usurp you despite getting this funny hat".)