But no bus, no flight, no ferry for sure.
I would not be quite so categorical for the above except for 'flights', and even there - commercial flights.
For buses (and I expect for ferries but I'm only guessing) - my
impression is that it really depends. The real question is whether the bus companies will let you board the bus or not.
The bus services
might be regulated as 'carriers' in the way that transport canada defines it (and it's my impression that there are bus services like megabus that are just not regulated this way, whereas greyhound might be).
But even if they're not it's (I think) a less serious issue for the bus companies than for the airlines, because they can just take the individual back to the nearest bus terminal (city).
And just as likely is that if the person is held up at the border, they can agree with the person to just leave them there. And if the person is already at the physical border (port of entry), then they will be admitted (they may just miss their onward bus - whcih, no big deal, get another).
Again, I don't know this for sure. But about the only way someone could test this is eg get to buffalo and then board a bus to toronto - if they won't let you board, there's your answer.
This is NOT advice. More just expressing that we might know how it's supposed to work, but then someone might find out that it's effectively not working that way at all in the real world. I hope someone tries and lets us know.
