Just to clarify:
1. All interpreters, whether certified or not, are supposed to keep interpreting assignment information confidential.
2. Certification is not a guarantee that the parties involved will not use information they are exposed to in an unethical manner. This includes anyone who has access to SSN's, credit cards, medical records, financial statements, etc. How many store clerks and restaurant servers handle your charge card? How many receptionists have access to your financial and medical files? How many government bureaucrats have access to your SSN?
3. In most interpreting situations, it's information in the ears, thru the brain, and out the hands, without "remembering" the details.
4. Whether or not certified, if any interpreter is discovered to unlawfully or unethically use information acquired from an interpreting assignment, it must be reported and acted upon. I can't imagine any interpreter being caught doing such things that would be able to continue in the profession.
5. Certification is a wonderful tool for recognizing which interpreters meet specific requirements. However, no one should become too trusting or dependent on that certification by itself. Certification is not the same as a background check or guarantee of integrity.
6. Certified terps aren't necessarily "monitored", especially private practice (freelance) terps. Who would do the monitoring?