Polite formalities are simply the way Yaone speaks but she's able to drop title usage upon request, at least. She gives Irisviel a gracious nod of acquiescence.

"I see. So it would seem today is unusual in more ways than one. Why do you think they are serving so much alcohol today? It seems to be a very odd choice of beverage to serve at an orientation and training session unless one wishes for those who attend to become intoxicated."

Yaone, being a poisoner herself, can think of several reasons why one might serve such drinks and all of them suggest duplicitous intent toward others.