Originally Posted by VamosRafaNadal
Yes. But I think (and it is the obvious thing to imagine, otherwise will be very stupid) that the player can't say "no" to a doping control if he meets the ATP workers; if the ATP workers don't find him (in the place and at the time that the player says) three times, then the player is punished.
A player can simply say that he can't pee, that he didn't have anything to drink and therefore can't pee. Sometimes it's as simple as that.