In an average pickleball volley, each side is only allowed 1 hit every time the ball reaches their side of the court. A double hit is considered to be a fault and can incur a penalty for the side of the court responsible for the fault. Such a rule would imply that any double hit warrants a penalty. However, there are some situations where a double hit could be considered fair play
The official pickleball rule book stipulates that in order for a double hit to be considered fair, it needs to have been performed as a result of a “Single-direction stroke, by one play"