We study voters’ response to marginal changes to the fine for electoral abstention in Peru. A smaller fine lowers voter turnout, but the effect of an exemption from compulsory voting is five times larger than that of a full fine reduction, suggesting that non-monetary incentives are the most relevant aspect of compulsory voting. We show that informational frictions limit adaptation to large-scale regulatory changes, causing our elasticity estimates to be substantially smaller than previous experimental estimates in the same setting. We find a negligible impact on representation, as 86% of the extra votes caused by a larger fine are blank or invalid.