It's impossible to provide "actual evidence" isn't it? Sure, maybe detailed log files are more convincing than a single (hypothetical) page saying "X did it". But as far as I can tell from online discussions I've followed over the years, more details just adds possibilities to find real or imagined faults with what you're releasing. Example: Barack Obama's birth certificate.
There just isn't a way to proof anything without resorting to either a trusted third party, or maybe (in the future) some application of cryptography. And the number of people or institutions enjoying widespread acceptance as trustworthy third parties is rapidly approaching zero, partly because this "don't trust anybody" shtick has become so common.
Gavin de Becker is a good example here. He is, or used to be, among those who enjoy some trust, at least among his profession. Extending trust based on such a track record is somewhat valid, considering the mechanism: a lot of his value as a witness in court, or the court of public opinion, rests with the idea that his reputation is always more to him than any single case. That logic isn't bulletproof, of course. But it's valuable to also consider the cost of the fundamentalist position that nothing short of 100% scientific proof should ever be considered: the absence of trust won't motivated people to better make their case, because that's near impossible with our current means. All it will lead to is more of the current free-for-all license to define their own "facts".