Yes, other errors raise the error events, it's specifically the "Record was not located" error I'm talking about.
To recreate, setup two TIBOQuery/TIBOTables pointing to the same record in the same table.  Don't set the IB_Transaction fields.  Then:
  qry1.Edit;
  qry2.Delete;
  qry1.Post;
and see if you get any error events.