http://www.amlegal.com/los_angeles_ca/SEC. 55.07. DEMONSTRATION EQUIPMENT PROHIBITED.
(a) No person shall carry or possess while participating in any demonstration, rally, picket line or public assembly, any length of lumber, wood, or wood lath unless that object is
one-fourth inch or less in thickness and two inches or less in width, or if not generally rectangular in shape, such object shall not exceed
three-quarters inch in its thickest dimension. (Added by Ord. No. 151,435, Eff. 9/6/78.)
TL;DR
If your stick is square, it must be 1/4" x 2" or smaller
If your stick is round, it must be 3/4" thick or smaller