Knights are expected to obey the request of the highest ranked present. Each keep has a captain with 3 lieutenants. Knights follow the Code of Chivalry. The code is not absolute and is focused towards good. A member of the black faction might actually try to be the opposite of this code. Also the tendency of the color as presented on the leadership page would override the code.
Unassociated men at arms are frowned upon and will be requested to come into training under a colored faction. Competition can be fierce and factions can become pushy. Once associated to a color, the actual service to the factions is generally loose and not overly controlling (unless there is a war)