Why Don't Clients listen?

I work as an Account Manager at premier SEO company Red Bricks media. I am consulting with clients daily and it amazes me how often our clients just choose not to listen to us. They hire us, pay us lots of money and then listen to only what they want to hear.

Today I discovered that one of our clients was breaking Google's terms of service by serving pages with duplicate content. Duplicate content is when you have the exact same content on two separate urls. If Google's filters detect this they can eliminate the pages from their index. That's bad. Before they built these pages we were very clear that the pages needed to be different. (Don't ask why the pages would be the same. It's a long story.) They decided not to listen and had to re-write 10 pages.

This happens all of the time. My friend who works for a cd duplication company deals with the same issue. I don't understand why people don't believe the experts that they've hired. Don't you think that you would give someone who actually works in the industry the benefit of the doubt? It is like George Bush not believing the scientists when they talk about global warming.

Anyway, that is one of my biggest pet peeves.