Players cannot play out of the rack. Chips must be stacked neatly on the table.
Reference
WSOP 2024 Live Action Rules
#61. Playing out of a rack is not allowed. If a participant decides to put chips in a rack before leaving the game, they must have an effective working stack of chips to play with that is not placed in a rack. Racks will be removed from the table at any time in the event that they obscure vision or impede gameplay.
