Smartphone usage in public spaces can raise privacy concerns, in terms of shoulder surfing and unintended camera capture. In real-world public space settings, we investigated the impact of tangible privacy-enhancing tools (here: screen filter and camera slider) on smartphone users' reported privacy perception, behavioral adaptations, usability and social dynamics. We conducted a mixed-method, in-the-wild study ($N = 22$) using off-the-shelf smartphone privacy tools. We investigated subjective behavioral transition by combining questionnaires with semi-structured interviews. Participants used the screen filter and the camera slider for two weeks; they reported changes in attitude and behavior after using a screen filter including screen visibility and comfort when using phones publicly. They explained decreased privacy-protective behaviors, such as actively covering their screens, suggesting a shift in perceived risk. Qualitative findings about the camera slider suggested underlying psychological mechanisms, including privacy awareness and concerns about social perception, while also offering insights regarding the tools' effectiveness.

翻译：在公共空间使用智能手机会引发隐私担忧，包括肩窥和意外相机拍摄。本研究在真实公共空间环境中，探究了实体隐私增强工具（此处指屏幕滤镜和相机滑盖）对智能手机用户报告的隐私感知、行为适应、可用性及社交动态的影响。我们采用现成的智能手机隐私工具，开展了一项为期两周的混合方法实地研究（$N = 22$）。通过结合问卷调查与半结构化访谈，我们考察了主观行为转变。参与者使用屏幕滤镜和相机滑盖两周后，报告了使用屏幕滤镜后态度与行为的变化，包括在公共场合使用手机时的屏幕可见度与心理舒适度。他们描述了隐私保护行为的减少（如主动遮挡屏幕），这暗示了风险感知的转变。关于相机滑盖的定性研究结果揭示了潜在的心理机制，包括隐私意识和对社会评价的担忧，同时为工具的有效性提供了见解。