I would get chosen for "random secondary" almost constantly when traveling CX 888 YVR-JFK, largely because the flight left at 10:30 PM to the US, and according to the CATSA screeners, they have to screen a certain number or percentage of travelers to the US, per their security agreement with the US. Given the small number of travelers, pretty much everyone on CX 888 would get screened, including me, on a biweekly basis. At least if these comments are correct, flyers from Canada to the US are more likely to get screened and even more likely if they are traveling at "odd" or unpopular times.