Brings up a discussion point: in a restaurant, place of worship, office, etc, are there anything that can provide cover? I remember back in the day we'd said the desk the Army uses (those grey metal ones) could stop a tank round. I'm guessing a 9 will punch through anything now days.
I've actually thought about this a fair amount. Most weekdays, I'm carrying a laptop bag with... a laptop in it. I figure those layers of leather, paper, and computer will stop most rounds. In fact, I don't even need the rounds to be stopped, I just need them to slow WAAAAY down.
Anything that has layers of resistance is better than nothing. (Do telephone books still exist in the wild?)