I know someone who works in gov (Australia, not US) who told me all about a FOI request that he was stonewalling. From memory, the request was open ended and would have revealed more than it possibly intended it to, and would have revealed some proprietary trade secrets from a third party contractor. That said, it was probably a case that would attract some public interest.
The biggest factors preventing governments from stonewalling every FOI case are generally time and money. Fighting FOI cases is time consuming and expensive and it's simply easier to hand over the information.
At least in Australia I gather it it somewhat common for FOI offices to work with an FOI applicant to ask them to narrow the request if it is so broad as to cost too much or take too long to process, or is likely to just to be returned as hundreds of black pages.
Previous FOI responses show more savvy FOI applicants in the past have also (when they don't get the outcome they desired):
1. Formally requested review of decisions to withhold information from release. This almost always lead to more information being released.
2. Waited and tried requesting the same or similar information again in a later year when different people are involved.
3. Sent a follow up FOIA request for correspondence relating to how a previous (or unanswered) request was or is being processed by the FOI office and other parties responding to the request. This has previously shown somewhat humorous interactions with FOI offices such as "We're not going to provide that information because {lame excuse}" vs FOI office "You have to. CC:Executives" vs "No" vs Executives "It's not your information" etc etc.
4. Sent a follow up FOIA request for documentation, policies, training material and the likes for how FOI requests are assessed as well as how and by whom decisions are made to release or withhold information.
5. Sent a follow up FOIA request for documentation, policies, staffing levels, budgets, training material and the likes for how a typical event that the original FOIA request referred to would be handled (if details of a specific event are not being provided).
Responses to (2), (3) and (4) are probably more interesting to applicants than responses to (1), (2) and original requests, particularly when it is clear the applicant currently or previously has knowledge of what they're requesting.
> The biggest factors preventing governments from stonewalling every FOI case are generally time and money.
Is there any backpressure in the system to make the employee(s) responsible for responding/signing off on the disclosure actually care about how expensive it is to fight a case? I would've thought they would think, "Well, the litigation cost doesn't affect me, I just approve/deny requests based on their merits."
The biggest factors preventing governments from stonewalling every FOI case are generally time and money. Fighting FOI cases is time consuming and expensive and it's simply easier to hand over the information.