There are certain larp-ish elements to the SCA, but if you imagine a scale from pure LARP to Civil War Reenactment type events, it's going to be a little closer to the Reenactment side of the scale. There are three main avenues to getting in-group prestige and the ability to lord oneself over everyone else; becoming a Knight through kissing the right butts on the battlefield, becoming a Laurel by kissing the right butts in the circle of people doing research and trying to force everyone else to be more correct in their historical reenactment, or becoming a Pelican by kissing the right butts in the group of people who actually make the group work (think the volunteers at conventions, only giving themselves titles and special decals to wear on their outfits). The people who actually bother to create a historical persona that is more than a name, country and date are pretty autistic.
The main draw for the SCA is going to a camping event where you pitch a tent in a field, engage in mock battles by day and build a bonfire for some heavy drinking, belly-dancing and general debauchery by night. The Consenting Adults moniker is certainly apt. The fight for Western Pennsylvania is probably Pennsic, which is a yearly event & the largest SCA event. They'll get upwards of 10,000 people out for that. They divide different areas of the country/world into kingdoms, and there are a variety of different inter-kingdom wars that happen yearly, in addition to inner-kingdom squabbles that merit camping out in a field to bash each other over the head with sticks.