Flying with USB/Serial0 plugged in (failsafes disabled)

I would like to fly with a mission computer connected to the USB port of a cube orange. The docs mention this disabling certain failsafes (i.e. battery failsafe), but I also see discussion about removing this feature from 2017. I was just wondering if this feature still exists, as well as any other changes that come as a result of plugging into the usb port during flight. Lastly, does this differ between plane and copter?