What happens if you import a category or tag twice in CSV field?

Does anyone know what happens if you import a category or tag twice in the same CSV field/record?

I am cleaning up records for an import. There is a chance that there might be some fields that could have multiple occurrences of the exact same category name or tag name in the same field of the same record.

I am wondering if Wordpress will choke on this or if it is smart enough to just ignore the second occurrence.