Since time immemorial (figuratively speaking - we all know that time immemorial actually finished in 1189), the MQL rules have included the following (under Guidance for Question Setters):
"Do not include questions with more than one, or indeed multiple, answers. Make sure each question you have written only has ONE correct answer."
It seems to me that this refers to questions where there is more than one answer, and any one of those answers - on its own - is correct. To give a trivial example: "Name a team that won the FA Cup in the 1970s."
What the rules don't seem to preclude - but I think most contestants will agree with me that it's a no-no - are questions that require two answers to be correct. For example: "Name the father and son who ... " This, I think, is what most of us mean when we talk about two-part answers (as opposed to multiple answers).
The reasons for this should be obvious to anyone who's ever played in this or any other quiz league; it's about getting part of the question right, but not enough to get the points – making it easier for the other team when it gets passed over.
I'm not sure why the rules don't explicitly preclude questions with two-part answers, or indeed whether they ever actually did. (Note to self: maybe raise this at the next AGM.)
In this example (where the answer is "Graham and Damon Hill"), the question would have been perfectly acceptable if only the surname had been required, viz. "What is the surname of the only other father and son to have become champions?"
© Macclesfield Quiz League 2016