I 'cut the red wire' because I had already removed the Raduino 5v regulator and modified my v3 boards audio to have a 5v supply (and the Raduino, USB hub etc) separately supplied from a small radio control 3A uBEC (you can see it, plus a small buss for 5v & GND feeds) on the left most side of the board/enclosure.
I also use the Win10 laptop for other things and when the laptop is on, the Raduino was powered up via USB - hence disconnecting the 5v feed from the USB from the computer side.
i also noticed that with both 5v feeds connected, sometimes it would cause the uBitx to reload/restart when interconnecting the USB cable.
I have no sign of any interference from the uBEC or the hub etc, so I'd say yes, cut the red wire!
Only downside is that when updating firmware, you have to have the rig powered up (as no power is supplied to the hub/Raduino via the computer USB port).
The upside is that I don't have to open the case to do firmware updates!