What did they expect? They are entering a neo-Fascist state.
There are direct flights from Vancouver to Mexico out of Vancouver, BC.. you never have to stop in the USA..
Just Say'in. Maybe you should plan better.
Don't even fly over the US. There is a chance that your flight might have to make an emergency landing, somewhere and you run the risk of finger prints, mug shots, interrogation, biometrics, strip search, cavity search ... particularly if you're a septuagenarian little old lady.
THE SKY IS FALLING the sky is falling!