I'm constantly making the point that customer surveys need to be well-written, meaningful, and relevant to the customer.
This is just a matter of respect: someone is doing you a favor by taking your survey, so don't waste their time.
But if that's not enough, here's another one. If you ask dumb questions, someone may mock you on TV, like Keith Olberman mocked a Minnesota Twins marketing survey yesterday.
Somehow I don't think this survey succeeded in promoting the Twins' brand image.