Triple dipping? Yes. Join ASCAP? Not if your profile is correct and you live in Canada.
Go to this page and start reading till you understand a few things. Pay attention to SOCAN. You have a lot of reading to do.
To be honest, I'm a Canadian, but I don't want to join SOCAN. To me, SOCAN is like a Blackberry, while ASCAP and BMI are like iPhones. The American stuff is always better than the Canadian counterparts.
I know in order to join ASCAP, you need to provide your US social security number, or tax forms, which I don't have. I'm currently doing some research on BMI, as they may have different policies for Canadians to join.
ASCAP has two types of membership: Individual and Publisher. Although Individual type won't accept me, I still have a chance. I own a small Canadian corporation, I think I can try to join ASCAP through that corporation as a Publisher member.
I love my country, but unless both ASCAP and BMI refuse to accept Canadians, I wouldn't even consider SOCAN.