It's is a violation of rules at every amusement park and a reasonably punishable offense according to the California Penal Code. If it were enforced more, most people would have more enjoyable visits.
California Penal Code
602.1. (a) Any person who intentionally interferes with any lawful
business or occupation carried on by the owner or agent of a business
establishment open to the public, by obstructing or intimidating
those attempting to carry on business, or their customers, and who
refuses to leave the premises of the business establishment after
being requested to leave by the owner or the owner's agent, or by a
peace officer acting at the request of the owner or owner's agent, is
guilty of a misdemeanor, punishable by imprisonment in a county jail
for up to 90 days, or by a fine of up to four hundred dollars
($400), or by both that imprisonment and fine.
(b) Any person who intentionally interferes with any lawful
business carried on by the employees of a public agency open to the
public, by obstructing or intimidating those attempting to carry on
business, or those persons there to transact business with the public
agency, and who refuses to leave the premises of the public agency
after being requested to leave by the office manager or a supervisor
of the public agency, or by a peace officer acting at the request of
the office manager or a supervisor of the public agency, is guilty of
a misdemeanor, punishable by imprisonment in a county jail for up to
90 days, or by a fine of up to four hundred dollars ($400), or by
both that imprisonment and fine.
490.6. (a) A person employed by an amusement park may detain a
person for a reasonable time for the purpose of conducting an
investigation in a reasonable manner whenever the person employed by
the amusement park has probable cause to believe the person to be
detained is violating lawful amusement park rules.
(b) If any person admitted to an amusement park refuses or fails
to follow lawful amusement park rules, after being so informed, then
an amusement park employee may request that the person either comply
or leave the premises. If the person refuses to leave the premises
or comply with lawful park rules, then the person shall be deemed to
be intentionally interfering with and obstructing those attempting to
carry on a lawful business within the meaning of Section 602.1.
(c) In any civil action brought by any person resulting from a
detention or an arrest by a person employed by an amusement park, it
shall be a defense to that action that the amusement park employee
detaining or arresting the person had probable cause to believe that
the person was not following lawful amusement park rules and that the
amusement park employee acted reasonably under all the
circumstances.