I too have received meaningless form letters from state and federal representatives. The FOIA kind of adds an edge to this in the sense that if we're asking, we're watching.

Another fun thing to do with FOIA is to prove that a document does not exist. Consider a point of authority and ask for a copy of the document that grants authority for such action. If they can't point to a law, and there is no document to support the action, then there is no authority for it, either.

I've done that a few times and it's a really cool feeling to see an agency admit it lacks the power to do something it had already done.