That list includes things like persons believed to be inadmissible; persons, other than Canadians, of course, who have been charged or convicted of a criminal offence; persons for whom a referral has been requested by Immigration, so if there's a watch-out or look-out that says we want to see that person; persons claiming refugee status or asylum; and persons intending to stay longer than six months.
Cette liste inclut notamment les personnes considérées comme non admissibles; celles qui—à part les Canadiens, évidemment—ont été accusées ou reconnues coupables d'un acte criminel; celles dont les services d'immigration ont expressément demandé le renvoi; celles qui demandent asile ou qui revendiquent le statut de réfugié; et celles qui comptent rester au Canada plus de six mois.