Absences pose a dilemma for theories of causation. Allowing them to be causes seems to make theories too permissive (Lewis, 2000). Banning them from beingcauses seems to make theories too restrictive (Schaffer, 2000, 2004). An increasingly popular approach to this dilemma is to acknowledge that norms can affect which absences count as causes (e.g., Thomson, 2003; McGrath, 2005; Henneet al., 2017; Willemsen, 2018). In this article, I distinguish between two influential implementations of such ‘abnormality’ approaches and argue that so-called ‘double-prevention mechanisms’ provide counterexamples against both.