Bottom Line analysis
OK, The lady committed fraud and forgery at the very least. Both are considered to be serious crimes. The fact that nothing bad happened as a result is really irrelevant. She still committed those acts against the charter company. They should have followed due dilligence and validated her certification... I assume there is some method to do so. If not, they certainly need to establish an ability to check the certification. It's not that hard with the technology available today. A phone call or an online check would verify that CERT#51745 belongs to Bill Smith, a 5'11" caucasian with brown hair and blue eyes, rather than some dame with a big rack.
Did they over-react by using the manpower to pursue an 8 month investigation??? Probably, but as stated by someone else there is a "perceived value" associated with the certification. If there really is an ongoing issue with forgeries, that will discredit the merit of that certification.
I think they were rather fair overall... no real harm came, so she just got a slap on the wrist, along with having her identity positively logged to make it clear to her that she can't get away with this again. End result, the MCA shows that they take care to protect the value of their certifications.
Was the DNA sample necessary or legally attained? That's questionable, but if she refused, they would simply proceed with pressing charges to the full extent of the law, then obtain the DNA sample while she was incarcerated.
Personally, if I attempted to attain a charter and they said I didn't have the certifications they required, I'd simply take my business elsewhere... as mentioned, it's not that hard to get a charter if you know the difference between a halyard and an anchor.