or they happen to present reasonable assertions that scrypt.cc couldn't possibly have the mining capability they claim they do, nor the payout rate they offer.

Posting evidence of withdrawals happening is asinine, it doesn't serve to prove anything as the whole point of a Ponzi scheme is to make sure you can keep paying out the small fraction of withdrawals that are requested, all the while seeking more 'investors' and, ideally, the current ones to keep on adding more funds back in.

It is when these schemes stop paying that it is already too late.