In my 25 years as a gca, I have testified in court five times, once for clients, and four times to defend golf courses or other friends in the industry. I turn down dozens of requests a year.
I am the perfect expert because I have gca qualifications, some national recognition (as former ASGCA Prez) and because I don't testify for a living, as so many experts do. In fact, there is a web site where lawyers can go to get experts and there is a section for golf courses. I know one ASGCA member is listed there.
For the most part, experts I have run across can be pretty unqualified, including golf pros, any number of consultants, etc. The legal standard as an expert is really pretty low. However, I suspect that lawyers (if these things ever got to court, which they rarely do) pick apart the qualifications of the experts as part of their case, so there is some "market demand" for higher qualification in the field.
I had one lawyer request my old testimony in other cases, my specs, my plans on old projects, etc. When deposed, those questions came up as in "Why did you spec this grass in 1989 if you now say its not the best choice?" (Well, it was then, and its not now, and by the way, these are different projects!)
All the more reason to stay away from it.....