I've found that some of the folks I took to lunch interviews were reluctant to ask certain questions because despite assurances that the lunch has no feedback, they didn't quite believe me (natural cynicism, I suppose). It was a shame.
Yeah, especially when your company has been doing some dirty works behind users' back and you think that users are bunch of idiots that never learn from their lessons and keep believing in whatever you say. What's a lame expectation.