I am not sure what you mean by "safety net," Michael.
From the client's perspective, buying seaside land is a major investment in the quality of the finished course. After they've made that investment, they could take two views: that they don't need a big-name architect because they've already given whoever they pick a big head start [see: Bandon Dunes], or, they've got a chance to do something great so they'd better hire the best in the business. Since seaside land is [except in very remote places] more expensive than architectural fees, most clients go the latter route.
From the architect's perspective, working by the seaside usually means great expectations, but it also means you get the benefits not only of good views, but sandy soils and a windy locale, so +++. That's an opportunity few would pass up. A safety net? I don't know. Contrary to Sean's post, there really aren't many people away from this web site who take the time to sort out what architects failed to live up to the potential of a particular site. I can think of several modern seaside courses that I don't think lived up to their potential, but nearly all of them are still in some top 100 list anyway. And to Sean's specific example, Half Moon Bay didn't cost Arthur Hills any work.
So maybe you're right, that they provide some sort of guarantee, but what they really provide is a great opportunity, that it's still up to the architect to make the most of, just like any other project.