In the BGA The Commish is the final arbiter of all that is holy and accepted. Whenever there is a disputed call he is the "opinion of last resort" and his decision is final (at least for the moment).
Decisions are based on fairness, congeniality and a liberal interpretation of the spirit of a round of golf among good friends. If you want a PGA ruling go to the USGA Rule Book; if you want to play a "ferocious but fair" round of golf then Ask the Commish to resolve any problems.
While rulings are final for the round in which they occur, they are "openable" for the entire Executive Board to discuss at the Ninteeth Hole and sometimes a modified ruling is adopted.