Rather than ask on FlyerTalk, which could result in significant informed and uninformed opinions, it might be better to check with an official source:
Delta Airlines Timatic page
Code:
/ 25MAY12 / 2016 UTC
National Canada (CA) /Transit USA (US)
Destination Japan (JP)
ALSO CHECK DESTINATION INFORMATION BELOW
USA (US)
VISA NOT REQUIRED.
TWOV (Transit Without Visa):
- All in-transit passengers For details, click here
Additional Information:
- Holders of a valid "C-1" transit visa issued by the USA are
allowed to transit to a third country as long as this trip
is 29 days or less and then transit again, as long as this
trip also takes 29 days or less.
...
Timaticweb Version 1.3
25 May 2012
or perhaps the US Department of State's Consular Affairs page regarding Canadians visiting the USA
here - which also has useful links applicable to this question.
As this is not particular to any specific airline forum, it will be relocated to the appropriate Forum for these issues. /Moderator