Well, in theory golf players are allowed to make calls themselves, but even if they do they often double check with a rules official before the score card is turned in if there is any doubt and depending on the situation they are even obligated to. But this is mostly if the ruling is very simple and black and white, at least unless we are talking about club tournaments.
In most cases, as soon as there are the slightest disagreement or a situation isn't crystal clear (or even if it is crystal clear, but they see a rules official nearby), they will call for a rules official. Not only on the largest tours, but also on every level where there is prize money involved. And in all non-amateur (and larger amateur tournaments) there will be rules officials driving around monitoring pace of play and give out warnings and penalties for that.