An unintentional double hit is not a hindrance. It is not a hindrance if a player stops playing a point because he believed his opponent is being hindered. In this case the player loses the point. If a ball in play hits a bird, this is considered a hindrance and the point is replayed.
Decision: The server’s partner and the receiver’s partner may take any position on their own side of the net, inside or outside the court. However, if a player is creating a hindrance to the opponent (s), the hindrance rule should be used. USTA Friend at Court, ITF Rules of Tennis, Section 26. The way I would paraphrase this rule is as follows: A doubles team can stand any where in the court they choose and it is not a hindrance unless they actually create a hindrance.
Singles players should not talk during points. Talking between doubles partners when the ball is moving toward them is allowed. Doubles players should not talk when the ball is moving toward their opponent's court. When talking interferes with an opponent's ability to play a ball, it is a ...
For example, if you ask the server several times to stop discarding the second ball after serving, and the server continues to discard the second ball, the action is considered an intentional hindrance, and you can stop play immediately and claim the point when it happens.
Also, it is not hindrance if a ball or any other object was lying on the player’s court when the point started. What about talking during play? For a singles match, talking is not allowed. And for doubles, talking is allowed between partners only when the ball is moving toward them. But if the ball is moving away from them, they should not talk.
In tennis, since the players are on the opposite ends of the court, physical hindrance is rare. It is instructive to provide some examples. Up first is making a deliberate sound to hinder a player’s opponent. In case it isn’t obvious from the previous sentence, sound is essential for appreciating the hindrance in the following clip.
Singles and Doubles. You can play tennis as singles or doubles. In singles, two players compete against each other, while doubles consist of teams with two players to a team. Mixed doubles is a variation of where men and women partner up and compete together. For the most part, the rules of tennis for singles and doubles are very similar.
Rule 26 of the rules of tennis defines a hindrance. It says: “[i]f a player is hindered in playing the point by a deliberate act of the opponent(s), the player shall win the point.” So notice two things there. First, the opponent's action has to be deliberate. And second, and this is important for doubles, the act can be of either or both opponent.