David and Jo fail to develop a system

Here's a brief description of the contestant's attempt. Someone's probably working writing up more detail!

David and Jo failed to develop any kind of system for determining when Gareth was telling the truth, operating instead by instinct and guesswork. They only got 1.5 answers correct in their quiz. Jo received a bonus point for being the best at recreating Gareth's party trick of making his tongue really big.

(Written by Taskmaster Wiki contributors)