Tax report reminder

[LeHack]

Every single income has to be reported using the cash register. Usually when something is paid in cash, the cash register is used at the spot to generate a receipt. At the same time when a bank transfer comes in often I don't have the register on me, so I update it later.
To make sure I have everything reported correctly it would be good to have an additional attribute by each entered payment which would state whether this payment was tax_reported or not. If it wasn't some reminder should be set to enter it by the end of the day (if possible). This could be done via the Android App, which could automatically generate a calendar reminder set for say 10 PM the same day a payment was added without "tax_reported" attribute set.