Yup, I've had weekend updates. They're infrequent though b/c they probably have a skeleton crew on shifts. Usually they're internal updates like when items are transfered from CP office to CP office (i.e. Toronto to Mississauga Sorting Plant). Don't think I've ever seen an "Item arrived in Canada" or customs updates.
EDIT: CP's been really slow/missing updates since the site went down this week. I ordered something from Jugglez yesterday and it arrived today, without any tracking info whatsoever from CP - usually CP has some info, however lacking it is