I cant believe that this person sent 0.1 Ether with 2,100 Ether transaction fee. I am pretty sure that this person is crying out right now and just shaking his / her head repeatedly. What will you do if this happens to you? How will you comfort your self at a time like this? 2,100 Ethereum for transaction fee really is a big amount and unfair on that person but a mistake was already made. I hope that he can contact the miner who processed that transaction for reimbursement which is I think possible. Look on the reference below.
https://etherscan.io/tx/0x1f73b43dc9c48cc131a931fac7095de9e5eba0c5184ec0c5c5f1f32efa2a6babLol, that was not a mistake, it was a good trick how to make your money legit - money laundering.
He did it 3 times, do you think that someone is so stupid?
Of course it can be a very good money laundering, and I completely agree with you. But I would like to take into consideration the only fact that the payment for the transaction goes to miners, and to whom it is very difficult to determine these coins. After all, we are talking about a specific purpose together, if it is a fraud.