Speaking of taking the piss. In my high school in Trinidad, our class would annoy teachers by agreeing upon an answer to write in if we didn't know the answer to any question. One time, we agreed upon a piece of bread for that year's final exams (all of them, not just one class). We nearly caused an upset in Biology when every single student in our class answered a free-response/write in answer correctly, with the same four words: 'a piece of bread' The question was 'name somewhere mold can grow.'
No. Most of us did. However given that we'd already been thinking about a piece of bread, that was the first thing that came to mind for a few, some others didn't know and some others decided it would be fun to write that in as one of the possible answers.