I noticed this rate on the Hilton res site a few weeks ago when I was booking the new Vancouver Airport Hilton. The note attached to the rate indicated one needed an out-of-country address to qualify. I booked the Bounce-Back Wkend rate, but may try the stop-ver rate in early December when I have an overnight at YVR (coming back from my 100K trip on CX). In this case, I'll have a valid international and connecting (next morning) ongoing flight.

As HHonors Gold, I am always pre-registered and just handed my package at the desk. Don't know if anyone would question the Canadian address on my file when preparing the package, flag it, and the desk ask me for the $50 difference between the stop-over and corp rate.