If anyone could add to the map, then the map would be a "fan map". If what we want is a community map, I would go for the forum's map, simply because this is the meeting point for the community.
I have added my own pin, and it was retained exactly as I have saved it.
Anyway, my money (and vote) is on the "Forum map"
I had only tangential contact with the Google Maps API, but maybe I can lend a hand in debugging this issue (if there is one anymore). Also, the "pins" can be easily changed to any image, like the *cough* *cough* official OXC logo...