Can it be turned off completely?
Yes. Caveat emptor.
How is it done?
Through an HID packet that can be communicated to you privately.
When will you add this feature to your other devices?
It may be added to future devices. It will not be retrofitted to older devices like your SpaceNavigator.
This is an internal adjustment. We reserve the right to remove this feature at any time without any notice whatsoever. If you have a specific project, I suggest that you buy as many SpaceNavigator for Notebooks as you will need for now and in the future.