Labour's latest policy to solve the problem of knife crime on the streets is to take youths found to be carrying knives around hospitals to show them victims of knife crime.
My understanding is that people carry knives mainly through fear of being attacked themselves. They don't rationalise the argument that carrying a knife makes you more likely to be a victim. Instead they see it as something of an arms race.
I would expect showing someone arrested for carrying a knife just how much damage can be done to you by someone with a knife is more than likely going to scare the person in to believing there is even more reason to protect yourself and that a knife is even more necessary.