The SCOC already dealt with the efficiency argument back in 1985 when it determined that the lack of an oral hearing for a refugee claimant before an independent tribunal was unconstitutional. See Singh v Canada (Minister of Employment and Immigration), [1985] 1 S.C.R. 177.  Singh also determined that any person in Canada even without legal status was protected by the Charter. 

The SCOC ruled the government's claim that giving hearing to refugees would be burdensome was too utilitarian a concern, and that administrative convenience would rarely be sufficiently compelling to justify infringing a Charter right.