This article analyses different aspects of illicit artisan work, especially in early modern Lübeck. It was a significant political problem especially for the guilds, because in their view it was a severe encroachment on their corporate liberties. In particular, the social control of clandestine artisans was a controversial issue: while the guilds regarded the right to carry out visitations as a central part of their privileges, this practice clashed with other civic liberties for example the protection of the ‘house-peace’ (Hausfriede).