Patron information is saved in the accountlines table indefinitely even if the charge was resolved. It would increase patron privacy if we could anonymize accountlines when they have been resolved, either immediately or after a set period of time. This could be based on the values in either amountoutstanding, status, or another field.
I have thought about the same thing, and agree it would be helpful in maintaining patron privacy. Some transactions, like Lost item charges, and automatic lost item fee refunds, could be scrubbed immediately (the same way 'issues' are scrubbed after return). But other types, like in the case of a manual payment for a book, the information on the title and payment may need to be preserved for a little bit to allow for refunds if the library allows (my library allows for a refund within 6 months if the book is found). Having different policies for different transaction types might be difficult.