[Paddlewise] Are USA<-> Canada flights internatonal?

I wonder if anybody has any comments on the following.
Alaska Air has International, Domestic and Canadian contracts of carriage.
According to their International contract, it allows 2 checked-in bags, 70 lbs
each :
 "The maximum weight allowance for each piece is 70 lbs and the maximum
outside linear dimensions of the first and second pieces are 62in each.
Maximum weight allowance will be 50 lbs. "  (Last phrase falls out of content,
- either it is 70 or 50, hell knows).

For Domestic (all flight is within USA) or Canadian flights limit is 50 lbs
per bag.
They do not have "North-American contract of carriage".

I'm still wondering why did they charge me $25 on my way back (only) from San
Diego, USA to Vancouver, Canada for excessive weight (wet folding kayak) of 67
lbs bag.

Both Domestic and Canadian contracts have overweight charge from $USD 50 up -
then why $25? There is $25 extra weight charge for travel between "points in
U.S./Canada and Mexico", though; but neither San Diego or Vancouver are in
Mexico, or have I missed anything? :-)

On my question - why didn't anybody care to charge extra on my way from
Vancouver to San Diego (kayak was dry, but food cans were plentiful), - the
check-in girl in San Diego responded with purely women logic: "Would you like
to be charged twice, or what?" :-).  I regret that have thrown away their
receipt - perhaps I should have sent it to their office and ask for comments -
I suspect they don't know what they are doing.
Alex.
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