So far, the debate over affirmative consent policies is yet to explore the possibility that affirmative consent policies might have a rationale that is acceptable to adherents of both the Mental View and the Behavioral View. In this essay, I articulate this independent rationale: each of us has a “Duty of Due Diligence” to take adequate measures to investigate whether our sexual partners are willing to engage in sexual activity. But on the assumption that someone had adequate evidence that their partner is willing to have sex only if their partner has clearly expressed this willingness, the Duty of Due Diligence would imply that affirmative consent policies need only be sanctioning behavior that is wrong in itself: the policies would sanction people who have wrongfully failed to ascertain that their partners are willing to engage in sexual activity. So long as these policies’ sanctions for this behavior are suitably proportionate to its wrongfulness, this provides a defense of these policies wherever that assumption holds. But by reflecting on the exceptions where the assumption does not hold, the Duty of Due Diligence suggests an alternative way of formulating sexual offence policies to achieve goals of affirmative consent policies: these policies could simply codify an institutional analogue of the Duty of Due Diligence itself. In other words, these policies could directly sanction someone for engaging in sexual activity without adequately investigating that their partner was willing to engage in this activity.