AHHHHH!
First off, there is a BIG difference between a Dr's recomendation and a "club card".
To be Legal in California, you need a Dr's recomendation. This is not a PRESCRIPTION, as presciptions are regulated under FDA. This can be obtained from your regular Dr. or you can see a MMJ specialist, here is a list for Cali from the CANORML site.
http://www.canorml.org/prop/215physicians.html
Now, lets get to the "card".
There are 2 types of "cards". One is California state issued and the other is issued from Patient Identification Services (formally Oakland Cannibis buyers club)
The state issued card can be obtained once you get a DR's rec from your county Health services IF your county has set it up yet.. Only about half of the counties in Cali have implemented this yet.
The other card is just an easy way to get into the clubs and not have to carry your Recommendation paperwork around with you.
Patient ID Services takes your Dr's. Rec and calls the actual Dr. to verify that you are indeed a patient of said Dr and that he did recommend MMJ to you as a treatment. Once this has been verified, you will be issued a "card".
Most all of the Dispensaries recognize this card and let you in.
Now, The State of California does NOT require you to obtain either card to remain legal in the system. The cards are only a matter of conveniance.
And NO, "they" do not track you. I have had my Dr's Rec since '96 and (knock on wood), have had no visits from LEO.