Not me, but when I was doing GCSEs we were doing Of Mice and Men and my english teacher said to my whole class every single lesson (no exaggeration) "there will always be a question on the fight scene with Lenny and Curly", "there will never not be a question on this", "make sure you have talking points on this scene perfected because there's gonna be a question on this" and so on.
My friend had just reread her A* essay on the fight scene and wanted to write it all down before she forgot it, so she opened the answer booklet and just went for it. It was only after she'd written it and half the time was gone that she went to the booklet to see what question number she should put next to it, and... no question on the fight scene.
She panicked a lot and did her best to answer the questions worth most marks and she didn't bother crossing out the fight scene essay and got an A overall.
Also, on a science test a girl missed the last 3 pages of questions - she got to the 4th from last page, turned it, didn't realise she's turned 2 pages at once, saw the desk, and figured that was the end. Fortunately, she'd done so well on the rest of it she still came out with an A.