(the empty et-al term is on purpose -- see first post above -- we'll use your first immediate solution)

Meanwhile, the revised processor (which will handle the singleton correctly)

@fbennett, I just came across this case the other day: https://github.com/citation-style-language/styles/blob/e88beb8b8e106ea7a14a464cd1c0e5de88425506/colorado-state-university-school-of-biomedical-engineering.csl#L30. In fixing up the style, I found that http://formatter.citationstyles.org/ currently converts <term name="et-al"></term> to <term name="et-al"/>.

Maybe we should add a note to the spec that explicitly discusses how non-defined (like <term name="author">...</term> which is absent from CSL locale files), empty (<term name="et-al"></term>), and singleton (<term name="et-al"/>) terms all should behave.