Full paper.
Bystanders have little say in whether they are being recorded by “always-on” cameras. One approach is to use gestural interaction to enable bystanders to signal their preference to camera devices. Since there is no established gestural vocabulary for this use case, we explored gestures to explicitly express consent (Opt-in) or disapproval (Opt-ut) in a particular recording. We started with a gesture elicitation study, where we invited 15 users to envision potential Opt-in and Opt-out gestures. Subsequently, we conducted a large-scale online survey (N=127) investigating ambiguity, representativeness, understandability, social acceptability, and comfort of a subset of gestures derived from the elicitation study. Our results indicate that it is feasible to find gestures that are suitable, understandable, and socially acceptable. Gestures should be illustrative, complementary, and extendable (e.g., through sequential linkage) to account for more granular control, as well as not be beset with common meaning. Moreover, we discuss ethicality and legal implications in the context of GDPR.