"No one expects..."
I'm afraid you're wrong, Kai. This question wasn't specifically addressed to me, true, and I may have been using it to make a point - but you should see how many phone calls and PMs and emails I get every day from people who buy things online, and who then can't figure out how to make them work.
Then I read about people choosing installers who can't figure out how to make things work. Why settle for doing business with people who are incompetent and then ask for free help? Why not find service providers who are competent?
So I was making a point as I answered the questions. Not all sellers are idiots, and not all installers are idiots, and the lurkers and noobs who come across the thread should have an opportunity to know that, that's all. Don't settle for ignorance, don't reward it.