>for your US employer
US/Canada have a very interconnected labor market, so in this context your comment is perfectly valid, and I would guess there are additional rules for this specific case. For literally any country other than US though, I don't see why it would be an issue for Canada or the country of origin, even if you do it repeatedly year over year.
Unless you're intimately aware of the intersection of tax and immigration law between Canada and every other country on the planet, that's a rash statement to make.
> Letting your employee be out of the country for 3-6 months every year on a tourist visa is a lot different from actually getting incorporated in that country and paying income taxes there.
Except that the company's responsibilities may extend far beyond just incorporating and paying income taxes. Every country's tax system is different and weird.
Companies don't require their employees to tell them their real address just to be mean, or to prevent labor arbitrage. They have genuine, legal reasons to do this.
My point, which I also made in another comment in this thread, is that law isn't code.
If you spend 3-6 months every year on a tourist visa in Canada working for your US employer, Canada's going to cotton on eventually and take action. If you do it a few weeks a year, you'll likely be fine.
Their test is "are you directly or indirectly competing with a Canadian worker?". If your employer is really ok with you being abroad 3-6 months/year then they should, presumably, also be ok with hiring Canadians or legal permanent residents to do the same work 12 months/year from Canada.