If that level of auditing were required, then I would recommend using a program that snifs the actual transaction log. That avoids both the ugliness of triggers and the insecurity of developers with ALTER PROCEDCURE permissions having access to the audit code. Of course, in order to achieve accurate data, users would need direct access to the tables and that creates a host of other security issues. Further, if you cannot trust your DBAs/database developers with ALTER TRIGGER but can trust them with ALTER PROCEDURE, then I think there are other issues at hand.

If you do not want users to have direct access to your tables, then I submit that you can't use triggers as the user affecting the change will not be available and that leaves putting the audit code in the stored procedures.