The only accident I recall was an Extra, (NOT an oldtimer!) losing power after T/O and going into a field.
That very same year a Bücker or Stampe biplane also
went into a field after engine failure...
With no people injured, such incidents typically do not attract too much attention. With warbird display pilots being typically very skilled, most of the airshow incidents do not result in injuries or fatalities.
Everybody should know that preserving our aviation heritage in flying condition is not without risk. Everybody involved should accept this. We are not talking commercial air transport of customers without a clue.
Restoring an ancient castle is also not without risk..
It looks like the people involved in the Convair preservation and transfer to the Netherlands did basically know what they were doing, they were skilled, they did it before. What exactly went wrong will most probably be discovered and all people in this relatively small community will learn from it. I know many people dealing with vintage and classic aircraft, all of them follow such threads carefully. Most of them are aware that they do
not know everything, and are eager to learn more. It is a pitty that a lot of knowledge gets lost constantly, but many people are working hard to preserve as much of it as possible.