The section makes no indication of this as an infraction only offense ...
SECTION 4103. CONSUMING ALCOHOLIC BEVERAGES: PUBLIC PLACES.
For the purposes of this chapter “alcoholic beverages” shall mean and include alcohol, spirits, liquor, wine, beer, and every liquid or solid containing alcohol, spirits, wine, or beer, and which contains one-half of one percent (1%) or more of alcohol by volume, and which is fit for beverage purposes, either alone or when diluted, mixed, or combined with other substances.
No person while in or on any public school ground, public school building, public building, or grounds belonging to the State, County, or other governmental entity or agency, shall have in his or her possession or consume any alcoholic beverage.
No person while in or on any unenclosed area designed or used, or intended to be used, for the parking of motor vehicles and which parking area is used in conjunction with or as any adjunct to any business, trade, or occupation for which a business license has been issued or is required to be issued pursuant to the provisions of Chapter 2 of Article VI of this Code, shall consume any alcoholic beverage nor have upon his or her person, nor in his or her personal possession, any container containing an alcoholic beverage, which container has been opened. (Amended by Ord. 211, adopted 11-13-62)
Additionally, the OP states that the cite was checked as a misdemeanor (which is standard practice for muni codes) even though they are most often filed as in fractions. It is the infraction that has the progressive penalties pursuant to section 1200 (which also spells out the penalties for misdemeanors).

