They use an emulator and record the player playing 18 hole custom course to get water boy award and then max XP for themselves and could also be the CC. They then simply press play and walk away.
Some players who know how WGT works would do it. We have seen a number of suspended/banned players who do that tactic and then get caught again because of their big mouths and they reach level of 100 plus in a matter of a couple of weeks.
WGT has been pretty good at catching them, deleting and removing those accounts as many of us who play mobile have noticed over the last few months that suspicious accounts get banned specially in wars when they post a few hundred million and no ones plays them in coin rooms. Specially given those newly formed accounts know what clubs to join and what to do to get access to clubs, etc.