Dale:
There are tons of namesake courses ... St. Andrews most of all, Pine Valleys, Oak Hills, etc. Most of them were named in an era when naming a new course was not a big marketing decision. Nobody was going to mistake St. Andrews in Yonkers, NY for the real thing, and the others were pretty generic names which just took on a new importance because one of them turned up on lists of the best courses in America.
Naming courses today is a bit different. The goal is presumably to find a new and interesting name to market your new course and make it stand out from the crowd, but there have been several examples of courses choosing similar names to a successful modern course, which sometimes appear to be an attempt to piggyback off confusion with the other. Sometimes it's just a coincidence, but sometimes it is not.
I guess trademarks might be the answer but I'm not sure they apply to golf course names, because there is already such a precedent of multiple St. Andrewses.