Recently used 'OSS' connecting US > Intl at YVR. There is no separation on the arrival hallway, after deplaning, for OSS eligible flights. If they are saying passengers from non-OSS eligible flights need to be re-screened prior to boarding their connecting flight, what prevents them from handing off their bags to OSS eligible passengers during the walk down the arrival hallway, before the security checkpoint?

I've only experienced Germany's and Switzerland's version of OSS - and there is physical separation between passengers arriving from "OSS" eligible flights - i.e. they are directed to different arrival hallways/levels.