Ask HN: request HITs on mturk.com from outside the US?

I live in Canada and am intrigued by Amazon's Mechanical Turk service. I actually want to do some market research, but am a bit stumped as to why only US residents are officially permitted to sign up and use the service (from a requester's point of view).

I don't particularly advocate this sort of thing, but is there any reason why non-US residents can't just put in a fake US address and proceed to get the results they need? Has anyone living outside the US successfully used mturk.com directly rather than one of the 3rd-party wrapper services?

This has been asked on HN once before (that I'm aware of) but with no responses - see http://news.ycombinator.com/item?id=624053.