They may not have discovered it for all we know. If you would like to take this one example as a sign of certainty then so be it. But I have been witness of 20 hours of sim time mistakenly logged incorrectly being questioned. The applicant addressed the issue appropriately and the discussion resulted in a positive display of his honesty. It could have easily gone the other way.

With that being said, is there a section in your ops specs that a SIC is required for Part 135 cargo operations in your PA31 or BE99?

You can log anything you want. How it is viewed by future employers is another subject matter. Anything interpreted as dishonest will automatically disqualify one from further consideration. Unless I am missing something you have failed to explain in the past few posts, whether or not this has been argued before, you can not legally log second in command time in any operation that does not require the position. Only those who need the time I can imagine would debate this point of well known FAR common sense among professional pilots.

My logbook was not perfect when I was interviewed. But there were no glaring areas to be questioned also.

One may not like this message on the reality of this subject, but the good news is that anything is correctable when honestly done so. Or roll the dice and HOPE it is not a concern for your future.