I think someone equally as smart as yourself thought of this already. The following all occurs in the NetServer.cpp file:
_ConfigureInterfacesFromSettings is called at line 746. Here the interfaces are checked in fSettings to see if they are disabled (706-711). If so, they are disabled and not set as a missingDevice if the interface is disabled (709). The next interface is checked…etc.
Checking for An Existing Network
On lines 716-720, a device that is found in fSettings (missingDevice), is set to the interface which is later added to the /dev/net within that (unnecessary?) if statement (772). The missingDevice will only be set and added to /dev/net if an entry does not exist in the settings already (716).
Does this look right?