Great story Darryl.
I did a Google on it and it's everywhere so must be true.
Reminds me of a smart arse answer I gave in an engineering "vibration mechanics" exam many moon ago. My answer was correct but used a very novel method to get there ... unfortunately I got zero marks, but it was fun escalating through the student union. Really made the professor sweat.
Although the professor had the last laugh...I had to resit my entire exam... properly!
Another useful exam approach I found (from Google) can be applied to more wimpy subjects like English as follows:
In an English exam I sat a few years ago while doing my VCE, we were given three pieces of writing, each with a set of questions attached. We were asked to "Choose one of the three exercises below".
While we were all sweating out pages and pages of answers, a friend of mine simply wrote "I choose number two", and did nothing for the rest of the exam. Since he had, technically, fulfilled the requirements of the paper, he had to be given full marks.
Almost all sample English VCE papers I've seen since then have the instruction "Choose and complete one of the following".