... and a vague "Below 20%" could be 19.9% (not good). Both conditions could prompt a review, particularly the latter. While, yes, credit card issuers like people who carry a balance, they don't like overextended borrowers. A ratio near 20% is pretty extended.
RNE, opining that good people with the best of intentions can nevertheless get into a fix and be unable to pay their bills. Banks still remember all the 2008 bankruptcies by people who had stellar credit scores.
There's no way that 20% utilization is considered "pretty extended" by banks unless the person has at least double or triple their income in available credit.