Seems like once again I'm being asked to protect those that have consiously decided not to provide for their own protection. Harsh? Maybe, but that's the way I see it.
If some lone wolf jihadist or just-plain-crazy seeking fame wants to shoot up the place where I happen to be my first priorities are to me and mine - and that usually revolves around getting to cover and then exiting the danger area (by miles if possible and/or necessary). If someone walks into the front of the store/restaurant while I'm closer to the back I'm very disinclined to run to the sounds of the gun. More likely I'll be looking for/using the back exit.
If some jhadist is in the process of sawing some other person's head off I am disinclined to immediately rush in and blow them away. The person getting their head sawed off most likely has already suffered fatal wounds and at the moment there is no imminent threat to me or mine, meaning I have time to place that 911 call and wait for the police to arrive. (I'm not sure what I would do if the beheader finished and tried to leave.)
Very often when I go out (alone or with other OCers) I am told by the people at that location that they "feel safer" because I/we are there - usually meaning our guns are there and we will use them. I've given up trying to explain that I/we are not cops and that there are only a few circumstances when I/we could lawfully use our firearms - and those are most often not the circumstances that the folks who "feel safer" are most worried about.
I usually get flack for expressing my position, but if it helps create dialog and thought on the subject I don't mind. All I hope for is that I am not backed into the corner of telling someone that if they want to be a sheepdog to the world they ought to join the police force.