Structural surveyors are engaged to provide a service. If there are essential repairs to be carried out then they must point this out. It's not a case of them simply covering themselves. This is precisely what the potential buyer engages them to do. Neither do they do this to put people off buying. We've heard of lots of cases of people moaning that their surveyors did not point out some (often trivial/cosmetic) issue. Now it seems that we have some people complaining that they do point out significant issues that may need attention. Damned if they do, damned if they don't in some cases.
I am not a surveyor by the way.