I regularly think in terms of decibans, where 10 decibans = 90% confidence, 20 = 99%, 30 = 99.9%, 40 = 99.99%, etc. From that perspective, there's as much difference between 99% and 99.9% as there is between 99.9% and 99.99%. Put another way, if 99% is the cut-off, then anything more than 20 decibans of evidence is ignored, even if the answerer has at least 40 decibans.