You know, his reddit account "Ofnieee" actually has a runescape account? it's a unique name aswell so I don't think it's a coincidence.
My money is on that Weath simply looked at that account, grabbed the registered email + did a quick search to see if he actually does own those accounts and then acted on it.
This:
Accounts can be found by bank items.
Accounts can be found by by quest statuses.
Accounts can be found by by skill levels.
May be true but it's not enough to qualify for a ban by simply posting the images alone on reddit. Jmods CANNOT get IP addresses from Reddit, the LE have a hard enough time pulling that information and about 3 years ago Reddit made it so logged in IP's are hidden from your account view. Reddit went into full rage mode when the admin changed a single comment from the database... There's no way they would do this for a small games company.
The dude also tried to sell the account on Sythe, sharing the exact same name.