Do you have to play if you can, in Block Dominoes?

I know that you must pass if you cannot play, but I haven't been able to find a definitive source saying whether you MUST play a domino in your hand, if you can play.



For example, if your turn comes and the board shows 3s on both ends, do you have to put down your 3-6 or can you hold onto it and opt to Pass? I know this is usually frowned upon, but is it against the rules?Do you have to play if you can, in Block Dominoes?
It depends on the game you are playing and which rules you are using. In most games in which the object is to get rid of your hand first, playing a playable domino on your turn is optional. You may be hurting your opponent by preventing him or her from playing, but you are hurting yourself as well by not shrinking your hand when you have the chance. In general, you can play it either way, but if there is a disagreement on which way to play, all of the players should vote on it. - LJS