bank is a perfect example of immutable accounting. once debit is posted to your account (let's say it is fraudulent transaction, or transaction entered by mist

bank is a perfect example of immutable accounting. once debit is posted to your account (let's say it is fraudulent transaction, or transaction entered by mistake), nobody will go and erase it as if it never happened. They would actually do reversal, by creating a new entry with the same amount and opposite sign. So you would env up with two transactions: +100 and -100. same is true for most accounting systems. Once the accounting period is closed (daily in banking system, monthly for most other companies), you can't change the closed month. All changes go as new transaction adjustments