Many authors take abnormality to shed light on causation by absences (e.g., Thomson, 2003; Clarke et al., 2015; Willemsen, 2018). McGrath (2005) proposed to delimit the absences that are causes by relying on (ab)normality and an increasing amount of evidence has been collected for the ‘categorical’ hypothesis that only abnormal absences can be causes (cf., Henne et al., 2017). This article raises some worries for such normativity approaches to absence causation by focusing on so-called ‘double prevention mechanisms’. In such mechanisms, one event causes another by preventing one of its preventers from occurring (cf., Schaffer 2004). A closer look at some of these mechanisms reveals that absences can be causes by doing exactly what they are supposed to do. I argue this feature indicates that (i) the categorical hypothesis is false, (ii) the categorical hypothesis does not follow from McGrath’s original proposal, and (iii) McGrath’s original proposal is false as well.