"Opal," muttered Foaly, after a long pause. "I think this has gone too far."
Opal looked up at Foaly in surprise. Foaly picked up one of the many tin foil hats off her desk.
"I know we need the money for the science fair but isn't this..." Foaly waved the hat in front of her, "a little unethical?"
Opal crossed her arms and gave him the cross look usually reserved for her Professors when they say something particularly idiotic.
"How so?" she demanded.
"How so?" repeated Foaly in disbelief. "Opal...we're selling people these hats and they don't work."
"What makes you say that?" she asked.
Foaly crossed his arms. Opal was as paranoid as he was but she certainly wasn't stupid.
"Assuming the human intelligence agencies actually can read our minds," he said dryly, "why would tin foil succeed when thousands of metres of rock have failed?"
Opal only smiled and put one of the hats on Foaly's head.
"Because Foaly... I made them."