[BrianG]

You could keep the red wire in the connector and put a small switch inline of the red wire. Then you can switch it off, which would do the same thing as removing the wire.

Or, leave the red wire in the connector. Then make/buy a small servo extention with the red wire removed. When you need the BEC, use only the ESC wire. When you don't use the BEC, use the adaptor on the ESC wire.