Are police trained to disarm someone attacking with a knife? If not, I'd suggest combat trained soldiers would have more confidence in a scenario where it would be inappropriate for them to be too heavily armed themselves, eg doing random stop and searches outside schools, in parks etc.
Opposite our house is a primary school. We frequently get parents parking on the yellow lines during drop off and pickup times. This is being tackled by putting up more noticeable signs telling them not to; also traffic wardens appearing at random times and standing near the school, which is very effective.
Perhaps penalties for carrying a knife should be displayed on signs, and specially designated personnel from the Forces be doing a similar thing to the above traffic wardens.
The other thing is drill music, which is supposed to be one of the causes of all this. It should be banned.