This policy setting allows you to control whether or not the user may alter the time before a password is required when a ...

This policy setting allows you to control whether or not the user may alter the time before a password is required when a device that supports connected standby's screen turns off.
 
If you enable this policy setting, a user on a device that supports connected standby may configure the amount of time after the device's screen turns off before a password is required when waking the device. The allowable time is limited by any EAS settings or group policies that affect the maximum idle time before a device locks. In addition, if a password is required when a screensaver turns on, the screensaver timeout will limit the allowable options the user may choose.
 
If you disable or don't configure this policy setting, the user cannot configure the amount of time after the device's screen turns off before a password is required when waking the device. Instead, a password will be required immediately upon the screen turning off.
 
Note: This policy setting only applies to domain-joined devices that support connected standby.