It is very easy to open a saved report or even to retain a configured report in an account tab by not closing the tab.  This sets up the possible scenario of having a report which is not able to be refreshed accurately if the chart of accounts has changed since the report was configured.

To warn the user if this scenario arises, I propose the following enhancement:

Include in every report configuration either a status bit called Dirty_COA or a fingerprint hash representing the Chart of Accounts as it exists when the report is configured.  If a status bit is used, reset the bit when the report is configured.  Whenever the Chart of Accounts is changed by adding or deleting an account, set this bit in every existing report in the custom report folder or in the account tabs.

Then, whenever the user selects the open report tab or opens any saved custom report, check this status bit.  If it is true, activate a warning in the report title that the Chart of Accounts has changed since the report was built and it may not accurately reflect the current information in the file.
Alternatively, if a chart of accounts fingerprint is used, compare the current fingerprint with the fingerprint saved in the report configuration.  Again use a difference to trigger a warning.

Refreshing an open report would not change the flag, but it would cause the flag test to be executed.