Shoulder surfing has been studied extensively, however, it remains unexplored whether and how it impacts users. Understanding this is important as it determines whether shoulder surfing poses a significant concern and, if so, how best to address it. By surveying smartphone users in the UK, we explore how shoulder surfing impacts a) the privacy perceptions of victim users and b) their interaction with smartphones. We found that the impact of being shoulder surfed is highly individual. It is perceived as unavoidable and frequently occurring, leading to increased time for task completion. Individuals are concerned for their own and other peoples privacy, seeing shoulder surfing as a gateway to more serious threats like identity or device theft. Participants expressed a willingness to alter their behaviour and use software based protective measures to prevent shoulder surfing, yet, this comes with a set of user defined criteria, such as effectiveness, affordability, reliability, and availability. We discuss future work directions for user-centred shoulder surfing mitigation.

翻译：肩窥行为已被广泛研究，但其是否以及如何影响用户仍未被探索。理解这一点至关重要，因为它决定了肩窥是否构成重大隐患，以及如果是的话，如何最好地解决它。通过对英国智能手机用户的调查，我们探讨了肩窥如何影响 a) 受害用户的隐私感知和 b) 他们与智能手机的交互。我们发现，遭受肩窥的影响具有高度个体差异性。它被认为是不可避免且频繁发生的，导致任务完成时间增加。个体不仅担忧自身隐私，也担忧他人隐私，并将肩窥视为身份盗窃或设备盗窃等更严重威胁的入口。参与者表示愿意改变自身行为并采用基于软件的保护措施来预防肩窥，但这附带一系列用户定义的标准，例如有效性、可负担性、可靠性和可用性。我们讨论了以用户为中心的肩窥缓解措施的未来研究方向。