One occupation which I have not noticed in the RV world is that of a surveyor.
In the marine world, unless you are experienced in the type of boat that you are looking for, you would not dream of buying without a survey first. I'm talking about used boats that will most likely be worth over $75K. Certified surveyors are not cheap so there comes a point where a small simple boat is not worth a survey.
Maybe that is the case of RVs. Who is going to pay a thousand for a survey of something worth less than $25K?