Whilst the 'bank error' is good news for one individual, it does raise the question about reversals.
Whilst long keys normally prevent hacking or other frauds, what happens if human mistakes are made?
What if we accidentally send coins to an incorrect address, or for incorrect amounts?
Is it possible to build in a 'recall' or 'oops' type functionality into blockchain transactions?
Should they be built in?
Time will tell
https://www.ccn.com/brazilian-crypto-exchange-mistakenly-sends-user-35-million-on-127-withdrawal/