Whilst I think you are absolutely right about the possible confusion, I would say that if BA were minded to let GGLs preboard, it would actually be very easy to circumvent that issue. Indeed, I have been in outstations where, for whatever reason, they wanted to organise some pre-boarding and did it without issue. A few examples:

- You just call passengers' names instead of saying "Gold Guest List"! It would typically be between zero and 3-4 GGLs on any given flights so "If Ms StarOne, Ms SpecialTwo and Mr FlytoomuchThree are in the boarding area, could they please come to the desk?"
- You just say "Guest List passengers" instead of "Gold Guest List" and voila...
- Or if you must use a rifle to kill a fly, as suggested upthread, you just create group 0.

Having said that, I don't think it is BA's intention to create a "super priority" boarding group for GGL and I personally suspect it is unlikely to be any time soon. By and large, boarding in group 1 is perfectly fine and if anything, the issue is more with the "group 1 2 3" queues and people clogging the boarding area in such a way that when group 1 are called they often can't get through at all.

PS: it is also worth remembering that not all GCH/Emerald, GGLs, SCH/Silver, F, J, pax etc want to board early. I know many who really prefer to come to the gate at the last minute and board last. I can be one or the other depending on the case. Some days, especially if I have a hand luggage that needs overhead space on flights within Europe, I will go to board very early, other times, especially if I am in F or CS and know that there will be no space issue, or if I only have my backpack with me and plan to keep it at my feet, I'd rather spend more time doing whatever it is I am doing at the airport or in the lounge and go and board after people have had a good chance to enjoy their wrestling competition. Sometimes, I even am at the gate area but voluntarily avoid stepping forward when group 1 is called if it looks too scrummy for my taste.