This question – with its very thorough answer – is from Gladys Grad, the Grand Master of American-Style Mah Jongg. Much thanks to Gladys for this great Q&A:

Everyday, we receive calls and emails asking us many questions about Mah Jongg social game and tournament rules.
     One such question involves exchanging Jokers in an exposure – specifically:  “Can a player exchange a symbol tile (like a 5 Dot) for a Joker, instead of the other way around?”
     As you know, the NMJL Rules do provide for exchanging a Joker for a symbol tile in an exposure.
     Because this question has come up so often over the years, we recently took a suggestion from a player to send out “some kind of petition,” to garner comments and remarks from others.   Basically, we assumed this form of starting the conversation would offer valuable insight.
     The premise suggested that there is an element of the luck-factor that may be reduced in the game, if players have the option to exchange a Joker for a symbol tile; thereby, opening up alternative strategies;
     1) to prevent an opponent from making a Jokerless hand (as exhibited by their exposures)
     2) to fill in a singleton or pair in ones own hand, that has been stymied by an exposure of  3 or 4 of the same tiles on an opponents rack.
     This was posted on a Facebook page a couple of weeks ago….and elicited many interesting opinions.
   
     The resulting comments from the Facebook page, and from the many calls, messages, and emails…indicated that our players are open to these kinds of discussions.  They appreciated the opportunity to discuss new ways to make the game we love possibly even more challenging. 
     We thank everyone who took the time to offer their opinions and comments. (Granted there were a few comments from players who adamantly opposed any change…and some who even said a few unkind words [they probably don’t make friends very easily]……but we welcomed the exchange.)
     Further, we feel that our personal and professional mission is to promote the NMJL game; ….and conversations like this one in our Mah Jongg community are worthy and constructive.Dreaming of those Jokers…