You know its a hoax only because scientists documented that it is a hoax.
See Coyote thats where you reveal how just the tiniest bit of PHD power can swell the smallest head to explosion. There was back then and always will be, plenty of doubters outside of 'peer review' halls.
And so if scientists had documented that Piltdown and many other debacles were not a hoax, what then?
Science is good when practiced by good men, and many advances can be made on science that is later proved wrong.
But fortunately, how the world turns and much greater questions, are not dependent on the latest greatest scientific answer for them, capiche?
I'm betting that there were millions and millions of Christians who, from the first day of it's discovery, believed absolutely that it was a hoax. Just because science finally agreed with them doesn't mean that they believed because of scientists.
Note that I don't have anything against science or scientists. Just bad science. Unfortunately much of evolutionary theory is just bad science.