User blog comment:LuffyPirateKing/From the Ritz to the Rubble/@comment-1595565-20111127203118

Well, destroyed here can be taken metaphorically. Remember Fukaboshi told Luffy to take them back to zero? That would destroy the whole belief that humans are evil and repair the relationship by starting over. That, coupled with the dust kicked up from the battle would make anyone think that they foresaw the island's destruction. To get Caribou, they place a bunch of hot mermaids out in the open as bait and wait for him to show up. They spring the trap, Luffy beats the ever loving crap out of him, and he is disposed of in the appropriate manner.