For example (also genuine question) what do you think would happen if anomalies were found? Would the general public get to know about them too?
One point to note that I think may not be appreciated - auditors don’t “work” for the company they are auditing. Their appointment is required by statute, and though their bills are paid by the company they are auditing, they have to be independent. To the extent that you can’t work on the audit of a bank if you have a credit card or mortgage with them. You can’t accept hospitality from the company. You can’t work on the audit of a company that your partner works for. Auditors work in the interests of the public, not the interests of the firm they are auditing. That’s a fundamental cornerstone of the role.
If anomalies are found, the auditor generally will not sign off the accounts (as it’s their professional reputation on the line, and they get personally pursued by the Financial Reporting Council* if they let shady accounts slide). This would be public knowledge.
Or, if they are not wholly happy, but not to the stage that they feel unable to sign the accounts, they will qualify them - “i.e. we found these discrepancies which have meant we can’t provide the standard certification.” (which is publicised). Or they resign (this is also publicised, and always leads to questions as it is an unusual step for an auditor to take).
*The recent FRC fines on KPMG for its not good enough audit of failed construction company Carillion is a good example - bear in mind KPMG were not involved in running the company, they just did not do a good enough job in investigating financial irregularities in its accounts. KPMG was fined a total of £35 million for problems with its audit, and the audit partner was fined £250,000 and banned from practising for 10 years. Three other employees who worked on the audit were fined £45,000, £30,000, and £40,000 respectively.