MARDA becomes MAR-D in ACIP->Tibetan. But who would
type in MARDA or MARAD or MARADA instead of MARD for
MAR-D? It's a likely error, one that a warning about
"Hey, you've got a vowel on a non-root stack!" would
catch. (I can think of one exception: GA-YA has a
vowel on a non-root stack, and we don't want to warn
about it.)