I quite happily wear my belt knife around our village - if I am off to use it. I seems that everyone knows that it is a tool.
At the show I would imagine that a great deal of the wearing of knives was for one major reason - and a perfectly reasonable one as it was a show - and that reason is show!
Showing off your pride and joy, custom, hand made, home made or just a Mora, is no crime - especially at a Bushcraft show!
Folk buy rediculously over spec cars and drive them in place where they cannot be used to their real potential - and others admire them for their look, potential performance, custom features etc.
No one bats an eyelid - but cars used irresponsibly (especially those that can exceed the lawful restrictions imposed on them for others safety) kill and maim more innocent people per year in Britain than any knife ever did.
Make people ashamed of their overspec motor vehicles before you make them ashamed of their sharps I say!
Ban folk driving to car shows before you get upset about people peacably wearing a knife on their belt.
Make unnessessary use of motor vehicles, driving when you could walk, catch a bus or train, driving for pleasure of just driving etc and you will save more innocent lives than by banning the carrying of a personal sharp tool - be it just to show off the knife or for serious use.
Be sure to prosecute anyone who uses a sharp for illegal reasons just as you would a driver who uses their vehicle in a dangerous way or in an illegal manner - any threat to innocent lives is just not on in my book.
Having a sharp in your hand when pshed is as bad as drunk driving, showing off with a blade in public is as bad as speeding or playing at handbreak turns on public roads ... but one boy racer can wipe out a bus queue of bystanders very easily, a prat with a blade my injure one (hopefully themselves) or at worst a couple of people before being stopped.
If someone wants to deliberately hurt another then I doubt that they will be searching out a bushcraft knife at a bushcraft show to do the deed...