I figured they would refund.
It does bring an interesting issue for a small pool.
https://pool.laurentiapool.org/#/workif this small pool had hit it . the software auto sends to the four addresses that have mined to it.
so that 25 coin block would go to four people. take 180 blocks to clear. and paypal/paxos would need to talk to four people to get a refund. not the pool but the four that mine to it.
I live in U.S.A. I would not be able to simply return the 7 or so extra coins I got. My address is registered and is kyc. thus it would look like I had a large taxable income.
Actually, no miner has to refund any transaction fee, even if it's 1000 bitcoins, simply no miner has to do that because there is no limit to bitcoin transaction fees since it's dynamic and fees are manually set from 1 to infinite, you can modify it the way you wish. So, I assume, no one can force any miner to refund, it's absolutely your gesture of goodwill to refund it.
To be honest, asking for refund of transaction fees looks like asking for refund of bitcoins that you sent to wrong address. If I send bitcoins to wrong address that doesn't exist, who is going to refund? This is nature of bitcoin, so, your wrong transaction fees should be taken over like wrongly sent bitcoins or lost bitcoins.
Like I said that small pool above will send me the fees which in the case of this error would be 7 or 8 coins of the 19 extra paid.
7 to 8 coins is very close to 200k.
I live in USA I report my mining my taxes due would be over 50k on that 200k close to 60k tax maybe 65k.
The pool above will send it to me automatically it will be in my hands. so I have a tax issue.
Another pool that could have done this is solo ckpool. you hit the block you get it all automatically.
So you would have 24 or 25 coins in hand.
f2pool most likely would freeze it and it would never go into the hands of the miners. so zero tax issues