Most people who carry guns are doing it for self-defense, not civil defense.
The rules of an Active-shooter event are:
Flee
If you can't flee, hide.
If you can't hide, fight back.
Carrying a concealed weapon doesn't change that. I have a little 380 pocket pistol I'll occasionally carry. It's low-capacity, low-power, and low-accuracy. No way am I volunteering to take on a psychopath with a long gun who isn't worried about collateral damage with my little pea shooter, and anyone Who expects me too just because I'm armed can kiss my ass.
I carry a pistol to protect me from muggers and car-jackers, not to protect the public.
Having the general public feeling that they need to carry a gun for self defense just sounds crazy to me.
Stabbings have risen here in the UK but generally it's either a rare occasion where some nutter is on the run or it's gang related. In general I would never feel the need to carry my own knife around for self defense. I don't know anyone who carries a knife around with them for self defense.
It's similar in a lot of states in the US. You aren't legally allowed to carry a knife for self defense, or as a weapon, but recently in my state, the laws were changed so that you can carry any size blade without a reason. So if you say "I carry a knife for defense" you'll get fined/arrested and your knife would be confiscated, but if you say "it's for cutting stuff" or nothing at all, thats legal.
Imo only an idiot would carry a knife for self-defence, especially if untrained. If someone (probably women especially) feels unsafe, carrying CS-spray would be more reasonable imo.