(Related, but not quite the same as, How should unfalsifiable claims be handled?)
What standards should be used when attempting to debunk "conspiracy theory" claims?
Consider as an example Has the US Government tagged people to be killed with stickers on the mailboxes? I suspect that the claim is false, but I am having trouble imagining what kind of answer would satisfactorily establish this.
Should we demand evidence that would convince a reasonable skeptic, based on our usual referencing standards (e.g. peer-reviewed journals, etc)? Such evidence is unlikely to convince a genuine adherent of the claim. If there really is a government conspiracy to kill millions of citizens, surely the conspirators would also be capable of planting misinformation in reputable journals, so they can't be relied upon. Anyway, most reasonable skeptics probably don't consider the claim credible in the first place.
Should we demand incontrovertible evidence, that would convince any rational thinker? ("Every US government employee has been interrogated under the influence of magical truth serum, and all of them denied the existence of the conspiracy.") This probably doesn't exist - by that standard, the claim is likely unfalsifiable.
Should we give original arguments as to the implausibility of the claim? ("If the government wanted to kill people, they would surely organize it in a more efficient way, using electronic records instead of mailbox stickers.") We generally don't allow such "theory answers".
Should we require that the asker specify in advance what sort of evidence they would regard as satisfactory? In that case, if what they specify is reasonable, we can attempt to search for it, without fear that it will be rejected as conspiracy misinformation. If it's unreasonable (they want magical truth serum interrogation transcripts), we could close the question. But maybe this places an excessive burden on the asker. We don't demand this of people asking more mundane questions; we apply community standards of evidence. Also, having the asker state their personal standard of evidence makes the question less generally applicable; a future reader might not find that particular set of evidence convincing.
Should we just leave such questions open and unanswered indefinitely, until such indeterminate time as incontrovertible evidence may surface?
Should we simply close all such questions? (What criteria should be applied in identifying "such questions"?)