I’m pretty sure Canadian DUI checkpoints are limited to interrogations about alcohol/drug intoxication (edit: and a few matters regarding the vehicle itself) unless something else is offered/observed.
Supreme Court basically agreed that they are warrantless and detainments without reasonable suspicion, but considered them acceptable for the purposes of preventing drunk driving so that’s all the carve out it for. See R vs Mellenthin here: https://torontodui.com/knowledge-centre/everything-you-need-...
(Worth noting that Canada’s constitution is basically toilet paper for a lot of things because a judge (or politician!) can override a lot of it)