Travel mode setting to save battery drain and prevent loss.
Make it so you can turn off or put all parts to sleep while travelling so the batteries do not discharge. Ideally initiate in the App or by holding the button on the Der's for 6 seconds. Wake would be by another 6 sec press of the button.
To be fair removing the batteries and installing the supplied covers does the same thing. You have to Cary the batteries in your carry on for air travel anyway.