This is the view of Michael Byers, a professor of international law at the University of British Columbia.
http://www.ligi.ubc.ca/?p2=modules/liu/publications/view.jsp&id=25
http://www.ceasefire.ca/atf/cf/%7B0A14BA6C-BE4F-445B-8C13-51BED95A5CF3%7D/Michael%20Byers%20Opinion%20Canada-Afghanistan%20Arrangement%207%20April%202006.pdf