Unscrupulous builders or ill-informed home owners?

There’s an on-going discussion on LinkedIn about who is responsible for the amount of inappropriate work being done on old houses.  Some blame home-owners themselves for not making sure they are getting the right tradesman to do the work, or are getting work done to a budget (well, we all have to do that!), and others (me included) blame unscrupulous (partly) and ill-informed (mainly) builders.  Home-owners cannot possibly be blamed, surely we have to trust whatever ‘professional’ we ask advice from?  I agree that owners are more likely to base their choice of contractor on budget but, without understanding the importance of the correct materials choices and performance (of little interest to most people) then it is squarely on the shoulders of the builder whose responsibility it is to ensure their customer gets the best result.  There is loads of training available, some of it free through CARS (Conservation Area Regeneration Scheme) in Scotland and THI (Townscape Heritage Initiative) projects and some over a day or two, even an afternoon at great venues like the Scottish Lime Centre Trust in Charlestown, Fife or the Scottish Traditional Skills Centre in Fyvie, so there is little excuse for builders nowadays to be ill-informed.  What they should be telling clients is that they don’t have the requisite skills to carry out the work.  There aren’t many builders who would admit to that!