I collect knives as I am an engineer & a good knife is good steel. A well made knife can be a work of art with very high craftsmanship. Yobbo's use stanley knives etc. available at any DIY but it is quality knives that get the bad name. My brother has lived most of his life around the Sheffield area & knew most of the old-time knife makers (cutlers). Some of their handmade knives are the best TOOLS I have for my woodworking hobbies. But illegal dealers only harm legitimate outlets.
Sorry to rant on but more people should realise that it is not the object that is dangerous but the person. (Remember the Glasgow gangs with razor blades sewn in their flat cap brims?)