Centralized sanctioning institutions have the advantage of promoting cooperation, while being highly stable. However, stability makes these institutions hard to change, which can be problematic when they implement ineffective or outdated norms. We consider a public goods game where a cooperative behavior is sustained by centralized punishment. We also assume that a different cooperative behavior is available and preferred by a type of individuals referred to as the newcomers. In general, newcomers cannot invade the cooperative population if they incur a cost when manifesting the new behavior, even if they inflict a cost to the existing population. However, prudent newcomers that manifest the new behavior if their number reaches a quorum and conform to the existing cooperative norm otherwise can be favored by social learning and fixate in the population. This evolutionary advantage can be maintained even if newcomers perform stochastic state selection (e.g. manifesting the new behavior with some probability also when conditions are not favorable) or if they have a distorted perception of the population composition (e.g., driven by propaganda). Stochastic activation provides an advantage to newcomers in the sense that some sacrifice to benefit the rest by damaging the existing institution. Our model highlights the importance of subtle identity signaling in social and political phenomena whose success is driven by decentralized and self-organized protest, and helps explain why many authoritarian regimes are extremely intolerant to any expression that may hide counter-establishment sentiments.