Originally Posted by
Rabidstoat
Post 9/11, a Canadian I worked with made monthly trips from Canada to the U.S. on an expires passport. She looked like a wholesome all-Canadian young woman, so maybe that's why she didn't attract concern?
It wasn't until a year into these trips that someone at the Pittsburgh airport (she flew Toronto to Pittsburgh) raised concern over it. She did get back home without too much fuss, but renewed her passport at that point.
Though she did have other forms of identification, and proof of Canada residency, she didn't have a birth certificate with her to show.
It would seem silly for them to put more reliance on a birth certificate than an expired passport-- the passport itself has the citizen's place of birth on it which is enough to establish proof of citizenship (even though the passport isn't valid anymore). She likely never had problems because up until recently, only "proof of citizenship" was required to cross the US-Canada border by air. Today, a "valid passport" is required.