Back on topic...
I don't believe this is a CASA cop-out at all. They are, in this case, the licensing issuer -as they are for pilots. It is IMO always incumbent on the employer to check that the qualifications presented are appropriate, valid and belong to the individual presenting them. If necessary (and where any doubt or suspicion exists) those qualifications claimed may need to be checked with training organisations, previous employers or CASA (the regulator).