If you check, many car shows do require that every vehicle entered in the show must have an extinguisher in it. The shows that I attend in my area even specify where it should be located, which is on the passenger side kick panel.
I'm curious what shows you are entering that require a fire extinguisher?
I have literally never had a requirement that I have a fire extinguisher in my vintage vehicle to attend a show, and if they told me where it needed to be mounted they would be told where to go, as no show organizer has the right to regulate safety equipment (unless it is a race event).
