Originally Posted by landrew

Does anyone know whether separate reservations are linked by the TSA system, such that a Canadian destination will be detectable if booked on a separate reservation (for purposes of using precheck from the US departure point)? They would both still be *A, but different airlines.

Unrelated, but interestingly there is now a Nexus lane (precheck equivalent I think) at security for domestic Canadian flights at YVR which I did not notice last time through. Very limited hours, though.

Transferring to US flights from domestic at YVR does not merit a precheck, of course because one is assumed to be an enemy alien when coming from Canada by air. In fact, when I inquired about it they didn't know what I was talking about.