While signing the petition during Ghosts Ahoy, players can stick to 2 ghosts instead of wandering around the port finding new ghosts. Should players attempt to talk to them after the quest while still wearing a bed sheet, their character will say "Wooo wooo woooooooo", to which the villager replies, "Sorry, I don't speak ghost."
After Ghost's Ahoy without a bedsheet on, they say:
"We do not talk to warm-bloods."
"What do you want mortal?"
"Why do we have to listen to that maniacal priest?"
"The cold wind blows right through you, doesn't it?"
"Worship Ectofuntus all you want, but don't bother us human."