In theory, no.  The player and the player alone is supposed to decide whether or not to challenge a call.\n\nIn reality, we all can see that coaches and even fans can have an influence on decisions made by the player on whether or not to challenge.\n\nIf you watch the umpire, they will say "It's your decision to challenge or not challenge".  They get no assistance from courtside.\n\nBut just wait and watch.  Abuses will begin to crop up here and there.