NO PENALY FOR MAKING A HAND PURE (Article 204)

Commentary: It is the prerogative of each player to use a symbol tile to do a joker exchange on their turn but they should count the cost. If the exchange results in that player declaring mah jongg on a pure hand (i.e., no jokers), the hand is doubled in value. The player who did the joker exchange does not incur a monetary penalty but they could hear complaints from opponents at the table.

Question from a Player: I exchanged the last joker from a player who later declared mah jongg with a jokerless hand and was told I had to pay for the table. Is this a rule?

Answer from the NMJL: Please remember that exchanging a joker or jokers may double the value of a hand making the player’s hand jokerless.

Source:  National Mah Jongg League Bulletin (2020 page 30 para 3)