[bubinubn]

Even when the burden of proof is a preponderance of the evidence, the accuser still has the burden the proof. The general rule seems to be more than 50% probability or "more probable than not." This is not a minor issue...if all you have as evidence are the testimonies of the accuser and and accused and no way to impeach either one of them, deference should still be given to the accused.

Also note that it is in general impossible to prove that something did not happen, as opposed to proving it did, as things that did not happen have no evidence of their occurrence by definition...