Not true - I'm a Canadian expat working in the US and I've had to deal with this myself. It really comes down to this:
- Canadian residents always pay tax to Canada on all income, no matter where it is made.
- Canadian non-residents do not pay tax on international income.
- Residency is determined by:
A) How much time you have spent outside of the country. If you have spent the majority of the year (6 months + 1 day) outside the country, you can claim non-residency. If you have spent the majority of the year in Canada, fat chance.
B) "Significant ties" to Canada. This seems draconian, but is actually not really. You can have a driver's license, space in a storage unit, or bank accounts and still easily make the claim of non-residency. Hell, I have a friend who owns a rental property in Toronto and still makes it.
- In any case, the whole process is much easier and less burdensome than the American equivalent. The first year you believe you qualify as a non-resident, you file a form with the CRA (Canadian equivalent of IRS) with your blank tax return (stating all income is international). Once you do that, you no longer have to do it ever again. I do not have to get my non-residency status constantly recertified.
It's all pretty simple. At the end of the day, if you live in Canada you pay tax on money you make - anywhere - and if you live outside of it you're basically just off the hook.
A significant tie could be as simple as owning a motorcycle, a corporation, or still having a Canadian bank account.