As the question implies, this would make an amusing crossword clue. But along with jokes (see Specialist Round 1, Supplementary 2) and things to which there is no definitive answer (see General Knowledge, Question 80) it is not (IMHO) a good quiz question.
This is not General Knowledge; it's lateral thinking. As with many things (see again Specialist Round 1, Supplementary 2), it's one thing to ask such questions in circumstances where questions are answered by teams and they have plenty of time in which to do so. In a League format, where individuals have a strictly limited time in which to answer, it's quite another.
It's great if you get the answer in time; but if you don't, and especially if (as is likely) someone else does, you just feel humiliated. And no one wants to be humiliated.
Another problem with questions like this is that once you've heard it, it will stick in your mind; if it comes up again, you're laughing. If you haven't heard it before, you're like the one that doesn't get the joke.
General Knowledge is about things you either know or you don't. Sometimes you can ask things that the contestant has to work out logically – I have no objection, for example, to questions that involve simple mental arithmetic. But lateral thinking, IMHO, should be avoided.
© Macclesfield Quiz League 2019