Hacker News User Advocates for System-Level 'Guest Lock' on Android and iOS

A user on Hacker News has published a proposal advocating for the implementation of a 'guest lock' system-level feature on Android and iOS devices. The suggestion aims to address privacy concerns when handing a smartphone to another person, proposing a mechanism that restricts device usage to a single active application.

The proposed 'guest lock' would lock focus on the current app, preventing the recipient from switching to other applications or accessing the home screen. To exit this mode, the user would need to input a command that triggers a standard system unlock prompt. The author noted that while this setup could potentially be bypassed more easily than a full device passcode using biometric unlocks, it establishes a necessary level of trust in social situations where temporary access is required.

To streamline the user experience, the proposal suggests that a dedicated hardware button could trigger this guest mode. This would allow users to quickly secure their device before handing it over, reducing the friction of navigating software menus to enable restrictions. The author highlighted scenarios such as showing a concert ticket or a photo, where granular control over what is visible is preferable to sharing the entire device.

The proposal also addresses a limitation of a basic guest lock: it does not prevent the recipient from scrolling through the device’s entire camera roll. To mitigate this, the user suggested a secondary feature allowing specific images or sets within the camera roll to be hidden from standard browsing. This could involve marking certain images as requiring privileged viewing or defining 'sets' that are hidden from general access.

The author argued that combining these features would provide robust privacy controls, such as hiding digital insurance records or personal photos, which they described as sensitive data best kept private. The proposal remains a user opinion and does not indicate confirmed development plans by Apple or Google. Current operating systems typically rely on app-specific permissions or full device passcodes rather than temporary, single-app restrictions.