It's a serious usability fault, not a clever hack. This test paper fails to comply with the user's expectations, like a webpage that breaks the Back button.
This all depends on where the onus lies. If you're developing a consumer-focused web application and your instructions are extremely complicated the onus is on the app creator to simplify. There are plenty of situations, however, where the relationship is really a partnership, and both sides need to fully get up to speed with each other. The Van Halen Case appears to be the latter.
Sometimes people have habits, like following their own expectations and assumptions rather than paying attention to detail and accurately comprehending clear, simple, literal instructions. These are good habits to test for, and good habits to break, in many instances. Not everything in the world neatly maps onto people's assumptions and intuitions.