Can audience embarrassment be used to shape interactions in public settings? Is this the threshold for an audience to step in and / or out of the interaction in performative interactions in public space? The proliferation of mobile and ubiquitous devices has shifted the attention to the design of interactive systems for use in public settings. This design applies the notion of performance to attract and engage audiences. Because performance becomes such a core part of the interaction, the success of those interactive systems heavily depends upon the physical, social and emotional context in which they are to be used. Indeed, strangers around a potential user may hinder or encourage that individual's participation in the interaction. Similarly, the physical space in which the interaction takes place, public or semipublic space may as well facilitate audience participation or prevent it. This paper investigates what characteristics of this setting (perceived / felt) can trigger audience participation in the interaction. A model based on the notion of performance and entailing some degree of felt embarrassment is applied to two cases to explain how the potential embarrassment implicit in any interaction in public space can be used to encourage users’ participation in it.