I witnessed something like this when I worked at a Six Flags amusement park (wasn't 6F at the time) that had a decent size water park. They did exit surveys every night, asking as many people as they could if things were ok, and one year they also asked people "Would you pay extra for the water park", it was free as part of admission. So they wanted to know if people would pay extra. People said yes. Something like 9…
Was maybe part of the issue that people leaving when the exit survey was being run (at "night") not representative of the visitors as a whole?