PICKING FROM THE WRONG END OF THE WALL (Article 69) 

Commentary:There is an expectation that all players pay attention to game mechanics, and if mistakes are made, there are penalties. When a player picks a tile from the wrong end of the wall, another player should declare their hand dead. If it goes unnoticed and more than one player picks from the wrong end of the wall, the game ends, and all the tiles are thrown in.

Question from a player:  What happens if I pick a tile from the wrong end??
 
Answer from the NMJL: 

• If a player picks from the wrong end of the wall, the player’s hand is dead, and the other players continue playing from the proper end. The tile remains in the “dead” hand.
• If more than one player has picked from the wrong end of the wall, the game ceases and the tiles are thrown in.
• If a player picks from the wrong end of the wall and discards, and another player calls that tile for Mah Jongg, the player who picked from the wrong end pays for the table.

Source:  Mah Jongg Made Easy (2024 page 20 #17)

Other answers from the NMJL:

“If a tile is taken from the wrong end and racked, the player’s hand is dead and the game proceeds from the proper end.  If it is noticed that more than one player has picked a tile from the wrong end, the game ceases and the tiles are thrown in.” 
 
“If you pick a tile from the wrong end and rack it, your hand is dead and the game continues.  If two or more players pick tiles from the wrong end the game is thrown in and is started over.”  
 
Source for other answers: National Mah Jongg League Bulletin Q&A (2018, 2019)