Showing cards while hand is live

[PantsOnFire]

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For tournaments from the TDA rule book. Rule #31

Exposing Cards- A player who exposes his cards with action pending may incur a penalty, but will not have a dead hand. The penalty will begin at the end of the
hand

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Robert's Rules SECTION 15 - TOURNAMENTS

22. Showing cards from a live hand during the action injures the rights of other players still competing in an event, who wish to see contestants eliminated. A player in a multihanded pot may not show any cards during a deal. Heads-up, a player may not show any cards unless the event has only two remaining players , or is winner-take-all. If a player deliberately shows a card, the player may be penalized (but his hand will not be ruled dead). Verbally stating one's hand during the play may be penalized.