TapNoiseClean Mode, the Mac lock screen and Guard Mode solve different problems. Choose based on whether you want to prevent accidental input, require login or notice physical disturbance.
Clean Mode: a short input hold
TapNoise holds key and pointer events for a selected interval. The display shows a countdown, and holding Esc for two seconds ends it early.
That is a convenience for a brief surface touch-up. It does not check the person’s identity and it does not replace shutting down for cleaning that requires it.
Lock Screen: protect the session
Control-Command-Q locks the Mac. Check Lock Screen settings for the password requirement after the display turns off or the screen saver begins.
A locked screen can still receive keyboard input into the login interface. It is therefore not the same thing as disabling keys for cleaning, and it does not physically stop someone carrying the laptop away.
Guard Mode: an audible deterrent
TapNoise can sound an alarm for supported movement, lid or charger events while it is running. Sensor availability changes which events it can detect. It can be stopped by force quitting or shutdown and provides no tracking service.
Use Guard Mode’s documented limits rather than treating it as a replacement for the screen lock or physical supervision. For a simple secure-away habit, lock versus sleep explains the Mac’s password timing.
Sources: Clean Mode, Guard Mode, Apple’s Lock Screen settings.