I don't think it is "clearly" a good idea... for a $400 survey to be worth it, the survey would have to find, on average, $400 or more in problems.  Is that really going to be the case in established residential neighborhoods full of tract homes, i.e. where most houses are?   My hunch is that it is not worth it when looked at from this perspective.  If the homeowner suspects that there might be a problem, I can see paying for an optional survey, but on an ordinary tract home in an established neighborhood, who is going to pay that if they don't have to? 

 Even in this case, I don't think you can claim that it was the lack of a survey specifically that caused the homeowner problems, since they could have gotten notice of the problem without getting a survey if 1.) the lender hadn't dropped the ball, or 2.) the Land Use office had filed the notices at the land records office. 

I stand by my initial feeling that this was a problem that could be fixed by having the code violations recorded so that they would be found during a title search.  Having one government office file something at another government office costs very little, and would have, in this instance, caught the same error that a $400 survey would have.