"Our old water torture was actually quite effective for making spies reveal what they'd learned," the chinaman informed.
"Oh? How was this water torture performed?" the islander asked.
"Well, we strapped the person in place and allowed water to continually drop slowly, drip by drip, for hours -- although the more stubborn sometimes lasted for days -- until the victim finally screamed for mercy. They would then tell us everything they knew."
"Ah.. and then you deported them," the islander replied.
"Certainly not! We wouldn't want them taking our secrets home with them!"
"We use a similar method but we use plums instead of water... then we send them home."
"Plums! And how can you keep them from stealing off with your secret information if you let them go home?"
"Who's going to believe them once they've gone plum crazy?"
8-)