Never in SF. A friend worked for a local company that got bought up by an east coast corporation. The new HR sent out an email that the new owner required drug testing. The local group announced, collectively, that they would not be participating. "But that's our policy!" "We'll all quit and have new jobs by the end of the day." "But that's our policy!" "Not anymore."

The local group won out, and the parent corp abandoned the policy of testing their California employees.