Still, in questions which have one correct answer (e.g. “Which is bigger, the earth or the sun” or “STALE is to STEAL as 89475 is to...”), I only mark the correct answer and “I don’t know” (if it’s there) as acceptable, and I mark the question as “Mandatory” if the “I don’t know” answer is available. It’s OK to be ignorant, but it’s not OK to not admit it.
I think that using factual beliefs to signal something other than knowledge about the world is a bad idea. It encourages lying to yourself and others.
Still, in questions which have one correct answer (e.g. “Which is bigger, the earth or the sun” or “STALE is to STEAL as 89475 is to...”), I only mark the correct answer and “I don’t know” (if it’s there) as acceptable, and I mark the question as “Mandatory” if the “I don’t know” answer is available. It’s OK to be ignorant, but it’s not OK to not admit it.