It seems that it would be impossible to prove something happened when it actually and absolutely did not happen.
What this tells me is our legal system is garbage and it often produces garbage results. I happen to know this anyway from first hand observation of it coming to the absolutely wrong conclusions in various cases.
Our legal system is crap. It needs reform. It should not be possible to prove someone did something when they did not actually do something.
There would also be fewer of these if juries took the guilty beyond a reasonable doubt standard seriously.