A butler's duty is to his charge. He is to see to their wishes above his own. He is only happy when they are happy and he is only fulfilled when they are fulfilled. Their orders are absolute and their wishes are first in his mind.

There is only one exception that is when their charge is at risk of harm whether from others or themselves. The it is time for a butler to act to his charge's wellbeing. Even if that means putting a Princess to bed.