The TDA Rule, #41, is quite clear just by reading the title "NO DISCLOSURE". It is a violation of the TDA Rule to disclose the contents or any part thereof of your hand. It makes no difference whether you are involved in the current hand or not.
From RRoP, v11, Section 15 Tournaments, Sub 22:
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.
There are some venue's that do not follow either and allow players to expose one or both cards and/or also talk about their hands. This is why it is extremely important to find out what the "house rules" are ahead of time. I believe the customs and typical house rules in Europe are different that those generally followed in the US.
Hope this helps!
