Yes, yes! People who have no experience with design should really not think they can do it themselves to save some money. 

I recently designed an InDesign newsletter template for a client who wanted to be able to layout their own issues. Needless to say they've done a terrible job keeping up with the standards the original design, and all their issues since the first one look HORRIBLE because they've done things like change the fonts, colors, and alignment, and even went so far as to break out of the preset two and three column layouts. Very sad. And the worst part is they don't even know how unattractive it is now. To them, it's more important to have saved money than to maintain an attractive brand identity.

To make matters even more complicated, customers really need to choose their designers carefully. There are plenty of "graphic designers" out there who have been in business for "years" but who clearly have no design skills whatsoever. Unfortunately, not all customers can tell "good" design from "bad" so there's a lot of bad design out there. 

Thanks for your analogy about using an amateur to  build a house, I'm going to use that one.

Sue Jenkins
Luckychair.com