In some situations when folks withhold evidence they hold within their exclusive custody and control and do not disclose it, especially when an ordinary person would perceive a duty or propriety to give disclosure, there can be a common-sense presumption that juries in litigation can apply, and voters during an election can equally apply, in voting.

As an example of a long standing and quite general principle, Kmetz v. Johnson, 261 Minn. 395, 401-02, 113 N.W.2d 96 (Minn. 1962) states in relevant part:

The general rule that has prevailed in this state permitting an unfavorable inference to be drawn from failure to produce evidence in the possession and under the control of a party to litigation is well stated [...]

"If either party to this action has failed to adduce evidence within its control which is reasonably calculated to throw light upon the conduct and responsibility of either party, such failure may be considered by the jury as tending to militate against the contention of such party with reference to the issue regarding which such evidence would have been pertinent."

In commenting on this instruction, we said:

"* * * The presumption, arising from the spoliation or suppression of evidence, that it would, if produced, be unfavorable to the party destroying or suppressing it, obtains with most force to the case of documentary evidence in the exclusive possession and control of the party. But the presumption is not necessarily limited to such cases. It is true that no unfavorable inference arises in ordinary cases from the mere failure to call as a witness one whom the other party had the same opportunity of calling or one whose testimony would be merely cumulative."

And there can be a common-sense presumption, depending on circumstances, of a collective will or effort to suppress, i.e., a presumption of evidence, if disclosed, being unfavorable is a presumption that need not be limited to any single individual and his/her nondisclosure. Really, it is just a matter of common sense inferences to draw from particularized facts of any situation, whether there is a moral or ethical duty to disclose situation details - it depends of course on circumstances, and no two situations are exactly alike in all aspects. In part, it's a gut-feeling of [im]propriety that can be determinative.