JimH wrote:

You also should have been reporting into Canadian customs
when you arrived in Canada.

I did. ;-)

Here's something interesting to consider, then.

The US and Canadian Customs share computer data about arriving and
departing vessels. I was standing in a US customs office waiting to
report and I overheard a phone conversation in which a customs agent
was detailing all of the previous border crossings for a specific
vessel going back about ten years or more previously. What struck me as
odd was that the US agent knew exactly when the vessel entered Canada
over the years- data that would not have been available except through
Canadian customs because as you know we are not required to "check
out".

If you're on the Canadian database as checking "in" to Canada and not
on the US database as having "returned" to the US, the evidence to make
life a bit awkward for you is alive and kicking. This is exactly the
sort of thing that can come back and bite you in the butt someday.