Pricing for keeps and above are explained in part by moats that are expected to block old courtyard runes... so effectively it'd be a single-shot opportunity at re-securing courtyards.
Probably because after the moat is placed and spots are marked on the draw bridge, that spot becomes once again compromised, unless there is some way to reset it, by removing and replacing the moat. Not sure how/if that will work.
Yeah i was under the impression you could reset the moat. Like when people turn on/off courtyards in he sign title. Free Bump