[s/v 'Faith']

Just a little grist for the mill;

The age old accepted 'doctrine' of anchoring says that he who anchors first does not need to re-moor (unless they drag from their original position).

I think that is why the space around a mooring is generally 'owned' by that boat... not for any legal reason. Some folks argue points on both sides to their liking... some as ridiculous as the idea they somehow 'own' the actual seabed...

The bottom like (pun intended) is the anchored boat can much more easily adjust their position then the one on the mooring. Now in the unlikely event someone came in a placed a mooring next to your boat while you were anchored all bets would be off, but I doubt that happens very often.

The other consideration is who is more likely to be aware and able to prevent collision of the anchored / moored boats. The laws are more clear there, and chances are the guy on the hook is present and better able to do something to prevent damage.