If you go to the University of Minnesota, it is pretty likely you have had an encounter with University Dining Services. UDS manages all the places food is available on campus. With 80,000 people on campus each day, you can imagine that is a lot of food.
Because the department is in charge of so much food for so many people, it is probably important to know what people think of them. Yesterday when I was grabbing lunch at the student union, I noticed a little area on the wall with sign that said "Let us know how we are doing!" A short survey resided next to the sign.
I thought it was a pretty good way to get responses, but with no one there prompting patrons of UDS to take the survey, I bet there is a low response rate. The only exception to this is when there are unsatisfied customers. I think people who are unsatisfied with the service they received are probably going to want to make their opinion heard more than people who thought their meal was just fine.