Just as an expanded view of language policy now affords agency to many more actors across society than authorities and linguists alone, it also accepts that the dispositions these agents bring to language affairs influence language policy processes and outcomes. However, this paper makes the case that language policy may also be guided, to some degree, by what these societal agents of language policy claim to "know" as facts in linguistics, regardless of the empirical accuracy of their knowledge. Drawing on an analysis of qualitative data from folk linguistic research on Maori language revitalisation, the paper discusses instances of the policy ideas and discourses of a cohort of young New Zealanders relying on what they claimed as facts about revitalisation. By bringing a folk linguistic perspective to language policy theory, the paper argues that space should be made to accommodate the power of folk linguistic knowledge in language policy theory.