They might, they might not; it is not a forgone conclusion.
So you are saying that the WHTI which mandates a passport for travel within the Americas has stricter commercial aviation rules than cross hemisphere travel? That's hard to believe.
I personally know of two recent instances of travelers using expired travel documents at a US POE with minimal delay. By minimal, I mean that a supervisor was called and said that the expired passport was acceptable, and it was a normal entry after that. Both were US Citizens. Using an expired US passport to enter the US just isn't that big deal, particularly close to the expiration date.
Was this POE an airport and were the travelers arriving by commercial air?
As for go arounds it depends on how well the CBP is honoring U.S. law that day. For example lawful permanent residents do not require passports to travel by air back to the USA, but at pre-clearance in Ireland and Canada it is 50/50 whether the CBP officer will demand to see a passport (and then chew up precious visa space with the stupid entry stamp). Before the WHTI mandated passports, I was hassled a few times for not having a passport when flying to the USA, and was told (lied to actually) that I would be required to have a passport in the future (contrary to the WHTI web site).
An unexpired U.S. passport or re-book the return to YYZ.
Originally Posted by
FlyingUnderTheRadar
Why not just use your French PP for the whole trip and deal with US PP when you return?
He would need an ESTA in order to ensure he boards the return flight to the USA using his French PP. What if he doesn't get the ESTA? What if the CBP fines him for obtaining an ESTA as a U.S. citizen?
Stuff like this is one of the reasons why I'm in no hurry to change my green card to a U.S. passport.