As an aside, and sort of pertinent to what bobrage mentioned, I have a friend who is Canadian and who is applying for permanent Canadian residency for her foreign spouse. Said couple have lived ALL over the world, as the husband was one of those fancy fancy expat package guys. In applying for permanent residency in Canada they had to provide a background check from every country they'd ever lived in. For these guys that was a LOT of background checking, and some of the checks, for off the beaten track countries, were almost impossible to procure after the fact.
I've had to get a Chinese criminal check for my husband's American visa applications. It was free and took about 5 minutes.