The Parks Department conducted surveys of visitors to Highland Park back in 2007 to see what they wanted for the Ridgewood Reservoir. The overwhelming majority of them said they wanted it to remain passive.
The Parks Department didn't like this result, so they redid the surveys, but this time excluded everyone who they thought would choose the natural option instead of ballfields. They also made sure the wording was vague so that the respondents thought they were referring to the entire park and not just the basins of the reservoir.
There's more here.