Stable isotope analysis is a new, not-so-secret weapon which promises much in mapping population movement on a regional and local scale. Lining up these movements with certain economic strategies, such as farming or foraging, with social strategies such as exogamy or with ethnicity and ranking constitutes forgivable temptation. Here our astute authors urge caution. Taking the Mesolithic-Neolithic transition in south-west Germany as their example, they show that caution does not inhibit interpretation, but opens the door to more subtle, more human possibilities.