Bad Reliance in Public Law

When should a legal system protect individual reliance upon an unlawful governmental act? From a rule of law perspective, the answer is: (almost) never. Strictly construed, the principle of the rule of law requires that unlawful governmental acts be invalidated and denied any legal effect. However, in some cases, the invalidation of unlawful governmental acts may be in tension with the need to respect the personal autonomy of those who made plans in reliance upon these acts without being able to discern their unlawfulness or without having adequate alternatives. The question of how to treat individual reliance upon unlawful governmental acts thus revolves around the tension between two basic duties of all governmental authorities, namely, the duty to adhere to the rule of law and the duty to respect the personal autonomy of those subjected to their power (whether these are their own citizens or non-citizens affected by their actions),