SoCal has hundreds of miles of streets (maybe thousands?) where parking becomes traffic at certain times.
We wouldn't have the towtrucks nor places enough to put all the towed vehicles, if these spots were full of towable vehicles when the clock ticked over to penalty time. Mostly people around here are careful to read all the signs that govern parking, and spend a minute to puzzle them out before leaving their car. A ticket or two usually drives the lesson home.
If the signs are contradictory or difficult to figure out, you can take a picture and make your case in court to have the ticket dismissed.