I would point out there doesnt appear to be any motive in hacking the account as to my knowledge he hasnt even tried to conduct any business. Putting a lot of effort into falsely claiming you are the owner of an account isnt logical to me in this case.
If it is illogical for a user to do A for R and that is your proof of ¬R then I vehemently disagree.
That is called an exploitable vulnerability. A flaw in reasoning. Illogical ≠ Impossible.