As VR expands into public spaces, new challenges emerge around spontaneous interactions between bystanders and unfamiliar VR users. While current VR systems often prioritize user awareness of their physical surroundings, they overlook the social dynamics affecting nearby bystanders. We conducted a deception-based study (N=80) examining how interface availability influences bystanders' comfort, confidence, and hesitation when interrupting VR users. We compared traditional static interruption interfaces (e.g., button on screen) with a proactive proxy that actively approached bystanders upon detecting interruption intent. Static interfaces, due to insufficient cueing, frequently caused bystander discomfort, leading to hesitant physical interruptions or complete communication avoidance. In contrast, the proactive proxy implicitly conveyed social permission, significantly enhancing bystanders' comfort and confidence. Our findings provide empirical insights into how bystanders assess availability and initiate interruptions with unfamiliar VR users in shared spaces, offering design implications for VR systems that support bystander agency and comfort during these interactions.
ACM CHI Conference on Human Factors in Computing Systems