If the RRID is well-formed, and if the lookup found the right record, a human validator tags it a valid RRID — one that can now be associated mechanically with occurrences of the same resource in other contexts. If the RRID is not well-formed, or if the lookup fails to find the right record, a human validator tags the annotation as an exception and can discuss with others how to handle it. If an RRID is just missing, the validator notes that with another kind of exception tag.