Canada is certainly not "too localized". Nor would be the U.S., the U.K., Australia, etc. Considering a country to be too localized for a Q&A site that talks about business and taxes and laws would be like Stack Overflow considering a programming language to be too localized and removing it from a question so it could be answered all in pseudo-code.
If the question is asked by a Canadian and pertains to him doing business in Canada, then let's provide the best answer in that context that we can.
There will be a variety of experts on board here — from all kinds of countries — and the most useful answers are those that don't gloss over important details. Tax jurisdiction is certainly an important detail when discussing invoicing and what is acceptable documentation.
Does that mean there may be similar questions but each for a different country or tax jurisdiction?
Yes and let's embrace it.
We handle these issues just fine over at the Personal Finance & Money Stack Exchange using location tags (and simply mentioning where you are, right in a question) and I invite anybody who is concerned about location tagging to drop by for a friendly visit :-) We've hashed out these issues over a few years and have a good grip on when a question needs a location tag specified, and when it doesn't. We have questions for the U.S., Canada, U.K., Australia, India .. and plenty of questions where location didn't matter.
Experts should ask for the location to be disclosed _ when it matters substantively _, and the OP should oblige, or else the question may be closed as not a real question, since it is too broad and not answerable in the current form.
Also, have a look at Joel Spolsky's post at The Wikipedia of Long Tail Programming Questions and Jeff Atwood's post Dr. Strangedupe: Or, How I Learned to Stop Worrying And Love Duplication. Quoting from that one:
It’s far more common to have many subtle variations of a question. I think that’s OK, because that’s how the world works. Trying to shoehorn a bunch of semi-related things into one arbitrary container in service of some Highlander-ish “there can be only one” rule is ultimately harmful. Remember: while there are aspects of wiki to our system, we are not Wikipedia. There is not one canonical question about every possible subject. Rather, there are many.
... much of that applies to the situation we're discussing here.
