Dave Smith wrote:

You were required to show it or you had it with you and offered to show it?
Passports are not required for Americans entering Canada, but I am counting
on reciprocity when the US imposes the passport requirement on Canada.

1) When checking in for a Canada bound flight the ticket clerk would not
issue a boarding pass unless I got out my passport. I was told this had
been the policy for over a year.

2) When going through Canada customs at Montreal the customs agent asked
to see my passport. I had to get it out of my luggage.

3) When leaving Montreal the USA customs agent requested me to show my
passport.