With classic bank transfer payment could be always reversed (even 30 days later). ok maybe for a banana this will not happens but it must be taking in account.
This is not true, reversing a bank transaction is not easy, you need to contact a bank and ask them to do so, and they will review your case manually. You only have a good chance of reversing a transaction if your money got stolen and you reacted swiftly. But banks generally rely of layers of verification to prevent that from happening.