From what I've been told by other architects, the majority of lawsuits about golf course design involve cart use, not the proximity of golf holes to one another. However, such suits do occasionally happen.
On past projects I've been told by lawyer friends of the client that such-and-such situation is dangerous and we can't build it that way. Unfortunately, once they've brought it up, my culpability in court would be about ten times as high if an accident ever happened there, so we must always relent to the client's wishes on liability issues. Oddly, I've only had a lawyer as a client once (actually twice, at Stonewall) and he allowed us to locate greens and tees much closer together than some other clients would, because of the quiet nature of the club.
The only thing I know for certain is that I pay a pretty healthy chunk of professional liability insurance each year. It really seems like a ransom considering the business I'm in.
P.S. This is another reason for the high cost of golf ... not the liability insurance itself, but the fear of liability issues causing most architects to spread out their holes more and more, which costs acreage and dollars.