As a 'victim' of a few FOIA requests, I can vouch for how much work goes into them. A favicon? Who cares when you've just involved 2 managers, a director and 4 mid-level federal officials? Some FOIA's were beyond reasonable and duly denied, but the reasonable ones could still take days.
Any costs incurred in responding to Freedom of Information requests are the price you pay for not being sufficiently open in the first place. If you pro-actively published everything that people are entitled to know (i.e. that you would have to release in response to a request), then these costs would be close to zero.
