Whether to commence or continue play in a stipulated round when fog is present is a difficult decision. Fog, by its very nature, is not easy to forecast, and it is challenging to predict when it will set in or lift.
From a playability standpoint, it is the MGA’s policy to commence/continue play in a stipulated round if the landing zones for all shots to be played are visible to the players. In this regard, tee shots requiring the use of drivers may present the most difficult challenge since such shots cover the most distance. Things such as fairway lines, hazards, trees, etc. in the drive zone must be visible to a large extent. However, the fact that visibility is partially obscured by fog such that the entire flight of the ball is not possible does not generally require a decision to delay/suspend play. In situations where two separate courses are being used (e.g. U.S. Open SQR), in the vast majority of cases if one course delays/suspends play, the other must, too. This should apply (i) whether the courses are near each other, and (ii) no matter the reason for delay/suspension (i.e. fog, lightning, etc.). Acting otherwise could present too many scenarios where players are treated differently and perhaps unfairly.