And customer education is paramount! How can people learn anything if they are not educated. This doesn't mean glossing over it and then setting it up wrong if the customer doesn't understand a brief answer.

1) Surround speakers are for immersion, ambience, to setup an environment in your listening space that emulates the action you are watching.
2) This means the amount of sound you get from the surround speakers, will be very dependent on the scene happening. A lot of times those speakers will have no sound at all for most of a presentation.
3) Demo an all action Hollywood movie with sound constantly going from everywhere (Transformers or something). Then demo a good movie that has more dialog.
4) Do you here sound coming from the rear speakers constantly in a movie theater? Are they setup wrong?
5) Try using the system setup the correct way for awhile, then let's see what you think.

Some customers just refuse to have things done properly. No amount of education or discussion is going to change their mind on wanting it setup wrong. For those, go ahead and press that all-channel stereo button for them or crank the rear channels up 10dB above the others. But I always explain their bad decision and also not to include my name in conversation about who did the system for them.