Man, that really blows! It really makes you feel helpless and even violated.

What does a garage space cost in the city?
At some point, the cost of the garage = cost of valuable equipment.

I guess your next step is to remove everything of value from the car.
I knew someone who just left their car unlocked with a sign in the window "NO RADIO".
They never left anything in the car and it wasn't anything special to begin with.
I guess that's the price of living in SF.

/bummed for you.