Walking away from your PC without first logging out leaves you vulnerable to shenanigans from co-workers. Whether it is an innocent prank or interoffice espionage, the end result is annoying at best. Microsoft seems to have realized this and is testing a feature in its newest Windows 10 Insider Preview build (15002) that, when enabled, automatically locks the Windows 10 device.
The feature is called Dynamic Lock, though engineers at Microsoft had been referring to it internally as Windows Goodbye. That is because it does the opposite of Windows Hello, a finalized feature in Windows 10 that can automatically log you into the OS using facial recognition, fingerprint scanning, or examining your iris. In contrast, Dynamic Lock adds a layer of security by logging users out when it no longer detects the user's presence, such as stepping away for a coffee break or to use the restroom.
Source: Windows CentralDynamic Lock might be overkill for most home users, but for workers in an enterprise environment who ware in possession of sensitive information, this could be a great addition to Windows 10. However, that is only true if it (A) works well and (B) works consistently. All it takes is one failed recognition for an opportunistic co-worker to pounce. Assuming it does work well and consistently, mashing the Windows Key + L could become an archaic practice.
It is not entirely clear how Dynamic Lock will determine when a user steps away. One possibility is that systems compatible with Windows Hello would factor in idle activity and lock the machine down after a set period of time. However, that could still leave PCs vulnerable if someone was able to swoop in before the system automatically logged out. It would make more sense to us if Dynamic Lock used a system's built-in webcam to determine when the user stepped away.
In any event this is one of many new features and upgrades included in the latest preview build.