FWIW, I don’t see anything wrong with Golf Courses remaining open and if not used as walking trails.
FWIW, if you do play golf, the 6 ft rule is obvious but far less risky that going to a supermarket.
The larger risk on a golf course is the irrigation water. Wastewater treatment IF it uses ultraviolet light and plenty of disinfectant (Chlorine) contact time in a contact chamber, then the tertiary reuse of water is probably OK.
Just remember, that secondary treatment of wastewater, which is what usually happens on a golf course, at best, doesn’t remove virus.
So the Irrigation water, if previously exposed to somebody infected, who say sneezes or spits on the ground, or wipes their ball with un-sanitized hands, might be contaminated with the virus.
Even if the golf course uses fresh water to irrigate, they typically are designed to drain towards the ponds, water hazards, where reeds and weirs provide primary treatment or irrigation water, and it is then recycled to waterfalls and to the irrigation system.
Even the spray from irrigation or water feature fountains might pose some degree of risk. Albeit rare, if there is risk in personal contact, then the risk also flows to recycled irrigation systems. If they tend to be safe, you should be able to smell the chlorine odor or mild bleach in the air around the ponds.
THey have been doing surveys of wastewater. They are finding a lot more COVID than they expect. It is a way to tell what the population of infected people are.
But even at elevated levels, the virus in water is not enough to be a danger.
I would not worry about wastewater being used for irrigation on a golf course. Assuming you are not showering in it, which is bad for obvious reasons.