I think this all depends on what you go to the shows for. The average member of the public cannot tell a Tiger from a Transit and probably does not care whether the vehicle they look at is 'genuine' or not. For them variety, however real or otherwise makes the show more interesting.
Living history does nothing for me but I know the public like it a lot, especially a good battle!
I go to shows to see the vehicles, meet friends, buy stuff etc. I don't feel aggrieved if there is a fake vehicle, any UN marked vehicle (for example) is of little interest to me, but that's just me.
It's a hobby , I am not on some crusade to make sure the public are educated and they certainly do not owe me a favour for showing my vehicle to them.