In this paper we will regard the task of operating a public mass exposition with several autonomous robots at a time. This implies questions regarding human-robot interaction, multi-robot control and interaction management. To enable human-robot interaction while guiding a tour we outline the SOUL environment. Multi-robot and interaction management are regarded with respect to visitor density and visitor flow. Concluding we will present and discuss results from the Swiss national exhibition Expo.02 in the time from 15.05.02 to 17.07.02, corresponding to 5293 hours of total robot operation time up to date and in interaction with 283319 visitors.