Most actors have very little education; many may not even have completed high screwl. Goodness knows they're not readers or deep thinkers, and it's clear that the ambient intelligence level among actors is not very high. But they are surrounded by handlers, schedulers, personal assistants, and other leeches who are supposed to be competent. It's up to these people to figure out what the protocol is in different situations once the idiot star leaves the studio.
Of course, there's only so much a personal assistant can do if the star is drunk, stoned, defiantly arrogant, or all three.
Stone probably just remembered that in every movie, the king and queen are already there, sitting on a dais, and the star comes in, walks up a long aisle of courtiers, and curtseys before the throne.