Multipurpose public displays are a promising platform, but more understanding is required in how users perceive and engage them. In this paper, we present and discuss results and findings from a two-day descriptive field trial with a multipurpose public display prototype called FluiD. Our main objective was to uncover emerging issues of interaction to inform future evaluations. During the field trial within a public research exhibition, people were able to freely interact with the prototype. Twenty-six persons filled out short questionnaires and gave free-form feedback. In addition, researchers in the vicinity of the display gathered observation data. Our main findings include the difficulties encountered with mid-air gesture commands, the lack of agency in case of larger interaction area, and the possibility for stepping out from the implicit-explicit continuum in the face of potential social conflicts.