Kneeling to royalty or the baronage (aka "Crowns" or "Coronets") is encouraged, if one is able, when summoned to approach the throne. It is customary for people to offer a "reverence" (bow, curtsey or the equivalent) toward royalty, their local representatives or their unoccupied thrones, upon coming into their presence for the first time in a day. Court manners are not expected at less formal events when garb is not required. Check out the kingdom and society web sites, or do a web search on "SCA court etiquette" for more perspectives.