Literally the miners are not liable to return back the money because they just what fee is used but when they know it is an error they returned it but we can't expect this to happen when the exact scenario repeats no matter the error amount if big or small.
Yeah that's quite true but this incident itself is repeated since I have seen this kind of incident taking place earlier as well.A few years ago somebody had mistakenly sent millions of dollars worth of crptyo as a transaction fee after which the miner had returned it to the address it was sent from. Ofcourse miners are not liable to return the transaction fee but we can see how these miners show humanity and return the huge loads of transaction fees. Obviously we can't expect to see it happening again and again. It is our duty to check all the details thoroughly before making a transaction in crypto.
