Authority derives from the status not any particular person. Obedience behavior change produced by the commands of authority. People have been taught from birth to obey appropriate leadership. Appearances can augment the atmosphere of legitimate authority, or create it entirely. That is, people who look the part of the authority figure are likely to be treated as if they are the authority figure, even if they are not.
Signs are another way to create the atmosphere of authority.
The TV show Candid Camera took advantage of people's obedience of signs more than once. When the sign showed DON'T EAT, people stopped eating. And customers only walked on the white tiles. Obedience to authority can have very serious consequences. Reverend Jim Jones created the People's Temple church and congregation, first in Indiana, and later California.