Quite true. I worked for BART Police for 7 years in the 80's, and there is a California Penal Code section that prohibits eating, drinking, or smoking within the BART system, and we regularly cited for it.

I posted in the original thread on this topic a month back. My comments then were basically that this woman could have signed the citation and taken it to court, but instead, when she was asked to produce identification, she walked away from the officer. If there is a local ordinance, you can't walk away from the police when they're going to cite you and expect they're not going to deal with it.