they can (or could).

if this is really within your threat model i suggest treating travel to the US much like travel to any other foreign hostile nation.

there’s plenty of articles written and some probably that apply better for canadians (written from the perspective of your own security agency)

basic advice like take a burner laptop and leave sensitive information at home.

here’s the aussie one.(1)

Good luck.

(1) https://www.smartraveller.gov.au/before-you-go/staying-safe/...