Feature request: permissions change history for auditing

Hi,<br /><br />As far as I am aware, there is no way to tell when a user/role was granted permissions or had
permissionsrevoked, or who made these changes.  I'm wondering if it would be useful for security auditing to maintain a
historyof permissions changes only accessible to superusers?<br /><br />Thanks<br /><br />Thom<br />