It's a kind offer but I don't think that there is much that anybody can do with them.

You are entitled to use the arrivals lounge if you are E or SE or fly in J. If you are flying Y and are not E/SE they won't let you in with those cards.

I don't use the arrivals facilities a lot since I live in London and only pass through YVR seldomly, but every time I have been in them they have cross-referenced my boarding pass with the flight manifest they have. I don't really know why they give those cards out other than to remind infrequent business class flyers about the facility.

I have occasionally heard phone calls to the arrivals lounge from either a check-in supervisor or the MLL saying that pax so-and-so will try to sneak in and should be stopped!