Originally Posted by
mtn335
That's just not true, though. In May I arrived from Toronto, walked from the domestic gates to the international gates, just wandered around, used the international Plaza lounge, and then went into US preclearance without leaving security. There IS absolutely access.
Ah, that's interesting. I forgot there could be a connection path through the D gates from domestic to the US side. That leaves one question, which I took to be OP's question: would US passengers be admitted to the main entrance to the D gate area? That seems very unlikely to me, but maybe I'm wrong.