I presume you got those tickets as a result of parking where you shouldn't have or the meter was expired and you were getting ticketed already? because I don't see the meter maid going out of there way to write tickets for no front plate alone because there is a exception in the CA. law that states if the vehicle did not come with 2 plates then it is not required.Technically if you're parked on a public road, you CAN get a ticket by those MeterMaids here in California. It's not a moving violation, but by not having one, you're obstructing them and law enforcement from identifying your car. It's also one less duty law enforcement officers have to deal with, when they could be focusing on hardcore badguys... The same applies for those people that would drive older cars with brand new dealer plates to avoid registration and/or paying fees. California eventually cracked down on that practice. I know you said you've been lucky not to get a ticket, but I've been ticketed twice while parked for not having my front license plate... And I also live in Los Angeles.
I have been more than just lucky I have a wall of tickets and not one for no front plate, I have been ticketed a couple times for front window tint which is illegal but that's it for "technical" violations.
bottom line I think is if you are up to no good and want to be completely legit, be legit
if you do not want a front plate don't have one and if you get a ticket so be it pay it and be on your way.
like I said I have had a couple for window tint, the ticket was like $275 I paid the ticket and left the tint on, not going to go thru the hassle of removing it and putting back on, I paid it and moved on I could care less part of living how you want to there not going to toss me in jail for window tint.