no what i mean is how easy is it to actualy tell all these things even with physical examination of the actual photograph rather than didigtal reproductions online.
is it easy or is it practically impossible (and so makes the "never proved fake" title pointless if its very hard to actually prove)
It would be impossible to prove it wasn't a long or double exposure if done properly. Thus anyone who claims that it has been proven not a fake is most definitely wrong.
So you have it the wrong way round, it is practically impossible not to conclude it was a long or double exposure.