Ticketed after letting me make a turn

SCENARIO :
I was on a street in downtown San Mateo, CA during lunch time.Street has Solid Double yellow in the center. I saw a parking spot on the left side of the street. Turn on my left turn light. Cop was coming from opposite direction on motorcycle. He saw my turn light and stopped. I waited for him to go but he just stopped there. I thought , may be he was letting me make the turn so I made it and parked. He stopped behind my car and gave me a ticket.
My point is he could very well have told me not to make the turn instead of waiting for me to make it and then give the ticket.
Can I fight the cop's incompetence / trap ?

Please help.
Thanks.

I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.

You could but the point is this: you have the responsibility as a licensed driver to know ALL the rules of driving, including when you can and cannot make safe and legal turn, u-turns, etc.

I totally agree with you. But there is also a rule which states that you are supposed to drive at 65mph on a freeway (101 in San Francisco bay area) but 99% people drive at 75mph. Similarly I have seen lot of people making turn on double yellow line.
I am not sure if it is ok to break the rule if everybody else is doing it.

To answer your question, just because everyone else does it and never gets caught doesn't negate the law nor your error.