Marlin, to my vision, you got too defensive to Stephen's reply. He is correct: you never know how those surveys may be turned against you. Although, your example with bank cards/SSN is strong and logical, I see Stephen's advice as to minimize the risk. You could as well shop with cash, buy tickets with cash through the agency, etc. Yes, it will cost more, but that's the price you pay to decrease the chance of being hit with something you told somebody in the past.
Since everybody's willing to take as much risk as the one can handle, it is totally your right to do it, but I would suggest you to (as pretty much Stephen's post does) to try being as secure as possible. To my knowledge, some of those websites may do lots of harm to your computer, as well as seed a virus/worm that will still your pass/logins to bank/credit card sites. And consequences to that are well known.

there is no free cheese, but in mousetrap