There is no night check on the multi and so no transport Canada examiner will go flying with you and allow you to log it as PIC in the journey log.
So students go flying with multi-operations incharge and for insurance reasons the club logs it as dual in the journey log whereas the student logs it as PIC in his log book for assessment purposes.
+Clubs do not let you fly as PIC(so as to be logged in the journey logs) unless you have 50 hours on a multi, Insurance requirement.