I have a question similar to, but not quite the same as, http://meta.math.stackexchange.com/questions/6676/review-of-low-quality-posts .
I was reviewing https://math.stackexchange.com/review/low-quality-posts/57285 , and I noticed that there was already a comment in it which politely asked the answerer to provide more background. For me this was the right thing to do: after all, just deleting the answer gives no clue on why it was done. In such cases, is it ok to mark the answer as "looks good" even it is not really good?