Don't buy a pig in a poke. A poke is a bag. The advice to not buy a pig in a poke is because a disreputable seller would place a cat in a bag instead of a baby pig, which is a similar size, and makes similar sounds. So make sure it's a pig before it's bagged. If an unlucky buyer met an unscrupulous seller, bought a pig in a poke, got home and opened the bag - too late, they let the cat out of the bag, and lost the evidence.
So DR buys pigs in pokes, then lets the cats out of the bags. Guy's a walking idiom machine.