Here is my two cents;
Look folks, it is not good to run away from your credit, however if you can't pay, what will you do? You don't pay, no matter you live in US or Canada. Although this is not a best route, but you can go to Canada and start a clean slate, unless you tell Canadian financial institutions or lending agencies your US credit, they can never find out, they cannot go into your Social Security and start reviewing it without you giving them permission as well as without knowing your social, the only way they may find out as you will go to the same bank in Canada, which you owe money in US and open an account and apply for credit, when that bank look in their database, they can find out that you are the same person who owe money to them.
In US it is a civil problem, not criminal, however if you did something purposely, like before leaving you pounded on your credit cards then they can come after you as a credit fraud, but since I am not a expert in this, this is just my guess.
Since you will leave US, you will not have any address/phone number, they will be keep looking for you and the law is 7 to 10 years, after that period is over, they will not bother looking for you.
Also, lets say, if you have to file your last taxes for the US, whatever address you will give to IRS, they will start calling and bothering over there. So you need to consider that while you are gone, which address to give for Tax Returns because you don't want creditors start bothering your relatives or friends for recovery.