The Locking Function of the Mixer is a good feature if the Desk is located on stage and the operater just sits in the audience with his tablet to work remote.
But sometimes the light from the Mixer light bar and LEDs might disturb the stage image (even with dark shows like black theatre).
Since nobody can operate a locked Mixer anyway i think it would make sense to switch off the light bar and most LEDs when locking the Mixer to reduce its light emissions to the lock symbol on the lock screen – and even to dim down the screen to minimum brightness.
Of course when touching the screen to unlock the Mixer that should be reverted instantly.