The standard ("expected consequences") idea is indeed to compare conduct options in terms of their expected pay-off. Conduct options with a certain, known outcome are valued by the utility of this outcome. Conduct options with several possible outcomes are by the probability-weighted mean utility of these outcomes (this is a sum of products, with each product being the utility of an outcome multiplied by the probability of this outcome). Now the question you raise concerns conduct options with possible oucomes whose utility and/or probability is unknown. This is often discussed under the label "decision-making under uncertainty" (as opposed to "decision-making under risk"). Generally authors advise caution. One rule reflecting this advice is the Maximin Rule: When the probabilities of outcomes associated with some conduct option are unknown, then assume that choosing this option will certainly result in the worst outcome it can result in. In other words, choose the conduct option whose worst outcome is...

A right to know is a moral orlegal claim, in principle enforceable, which a specific person or grouphas against another specific person or group that the latter notwithhold specific information from them. Such a claim typicallypresupposes a certain kind of relation between the two parties as wellas a strong need or interest by the second party in the information.For example, an uninfected woman has a strong interest in knowing thather partner is HIV-positive and, given their relationship, she has aright that he inform her. There may be third parties (mutualacquaintances, for instance) with a moral obligation to tell her (ifthey know). But this obligation does not normally correspond to a moralright on her part against them. The absence of a corresponding moralright means that the obligation is not enforceable: While it would bepermissible to criminalize her partner’s withholding of theinformation, it would not be permissible to criminalize suchwithholding by third parties. Talkof a right to...