From someone with very limited knowledge of FF miles, etc.
I would think that a person could NOT "buy" two seats on the same flight in his/her name (though I guess people who need the extra space may get an exemption...but not double the rewards). So, maybe the Cellist made up a bogus name/etc for his traveling companion(cello) and it took Delta 11 years to find out that was what he did. In this cause, I would say he defrauded Delta and should be removed from the program.
(I did not read the article)