APPENDIX K ITF RULES OF TENNIS THE LET DURING A SERVICE (RULE 22) “NO LET” RULE This alternative is play without the service let in Rule 22a, whereby a serve that  touches the net, strap or band is in play. At the discretion of the sanctioning body, when playing doubles using Short  Sets in combination with No-Ad scoring and the No-Let rule, either player on the  receiving team is permitted to return a serve that touches the net, strap or band  and lands within the correct service box. The referee is the final authority on all questions of tennis law and the referee’s  decision is final. In matches where a chair umpire is assigned, the chair umpire is the final authority  on all questions of fact during the match. The players have the right to call the referee to court if they disagree with a chair  umpire’s interpretation of tennis law. APPENDIX VI ROLE OF COURT OFFICIALS In matches where line umpires and net umpires are assigned, they make all calls  (including foot-fault calls) relating to that line or net. The chair umpire has the  right to overrule a line umpire or a net umpire if the chair umpire is sure that a  clear mistake has been made. The chair umpire is responsible for calling any line  (including foot-faults) or net where no line umpire or net umpire is assigned. A line umpire who cannot make a call shall signal this immediately to the chair  umpire who shall make a decision. If the line umpire cannot make a call, or if there  is no line umpire, and the chair umpire cannot make a decision on a question of  fact, the point shall be replayed. In team events where the referee is sitting on-court, the referee is also the final  authority on questions of fact. Play may be stopped or suspended at any time the chair umpire decides it is  necessary or appropriate. The referee may also stop or suspend play in the case of darkness, weather or  adverse court conditions. When play is suspended for darkness, this should be  done at the end of a set, or after an even number of games have been played in  the set in progress. After a suspension in play, the score and position of players  on-court in the match shall stand when the match resumes. 468