It depends on whether or not there is a local ordinance prohibiting such containers. See Business & Professions Code § 25620 which provides (a) Any person possessing any can, bottle, or other receptacle containing any alcoholic beverage that has been opened, or a seal broken, or the contents of which have been partially removed, in any city, county, or city and county owned park or other city, county, or city and county owned public place, or any recreation and park district, or any regional park or open-space district shall be guilty of an infraction if the city, county, or city and county has enacted an ordinance that prohibits the possession of those containers in those areas or the consumption of alcoholic beverages in those areas; (b) This section does not apply where the possession is within premises located in a park or other public place for which a license has been issued pursuant to this division; (c) This section does not apply when an individual is in possession of an alcoholic beverage container for the purpose of recycling or other related activity.
The City of Irvine municipal code says that the City does not allow open containers with alcohol in public places, including parks.
There are exceptions to the general rule. People who are hosting events in public places like parks may ask the City for permission to serve and allow guests to consume alcohol in the park. People may also ask the City for a permit or license to sell alcohol in the park.
The code also does not allow consumption of alcohol in "open space areas." This likely includes undeveloped and "wooded" areas. Exceptions may be authorized by the director of community services and the city council.
An Orange County ordinance also prohibits consuming alcohol in a public place unless you have permission from the owner or the person who has permission to hold an event in the place.
You also may run the risk of violating the state law prohibiting public intoxication.
At the end of the day, unless you are at an event that allows consumption of alcohol in the public place, you may run the risk of getting charged with an infraction for violating a city or county ordinance, and possibly a misdemeanor for violating a state law.
Relevant City of Irvine Laws
Relevant Orange County Law