While perusing the Stewart Tartan Pipes and Drums "days of yore" page, I came across this interesting tidbit:

NOTE: Historical research reveals that, prior to the recent pipe band, the Wallace Guard, Second Brigade was a California State Militia mustered 28 July 1855 and disbanded on or before 1860. The unit was known for its Highland dress and the providing of elaborate entertainment at social functions and the staging of a grand ball at the International Hotel. On 3 June 1856, the Wallace Guard and other State Militia units refused to take arms and fire upon the citizens of San Francisco by a proclamation by Governor Johnson. Johnson declared that a state of insurrection existed in San Francisco and that all companies report to MGen William T Sherman. The unit temporarily disbanded as a result. The unit also took part in the Atlantic Cable laying ceremony in September 1858.

-- http://www.stewarttartan.com/v3YORE.htm#Wallace_Guards
Here is more information from the California State Military Museum's web site:

http://www.militarymuseum.org/WallaceGuard.html

An article from a 1959 issue of the CA Historical Society Quarterly notes that the Guard was present at the Inaguration of Governor John in 1856, "attired in colorful plaid Highland uniforms" which contrasted the other companies attired in more "orthodox" garb.*

*"Polish Boot and Bran New Suit: the California Militia in Community Affairs" by Dello Dayton.

Note that the Wallace Guard refused to fire upon citizens during the Vigilante days in the history of San Francisco.

Regards,

T.