Originally Posted by todd-r
If I have a night flight out of SEA and will be driving to SEA from YVR, can I check in using the ITM at YVR for my flight departing from SEA (ie. earlier check-in for upgrade)?
Nope, sorry... ITMs only check in for flights departing from that city (plus appropriate connections of course). It won't even work for co-terminal origins - you actually have to be in the airport you're departing from - or hotel lobby in places like SEA.