The same restaurants that last month re-started indoor dining basically on the honor system are now asking to see your CDC card - I don't carry it around all the time, so luckily I had a photo of it on my phone today, and the maitre d' accepted it.
He even had a good tip, which I assume means the issue has been coming up a lot, which is to email the photo to yourself and put it into its own folder or other keeping-spot on your phone so it's easy to bring up.
This is another way in which San Francisco feels so European :-)