Companies are may be the same, but they only store records and they are not banks who are lending you money. You will put your name and date of birth and SIN, your credit in Canada will come up not the USA one, these companies are not working for banks that they start investigating you further around the world that if you ever had a bad credit, they don't have your PR file that they know you lived in Europe, US or Australia etc. The question is, can they find out? sure they can if an agency like FBI in Canada ask them to investigate.
They don't do a background checks of any kind, all they do is store public data. They are Data storage companies and not working for the banks that they investigate each applicant further and further unless some kind of government is involved, legal issues or criminal problems then authorities asked them to do so otherwise they will not be able to tell you what you had in the past in other countries. Of course, if you had bad credit lets say with Bank of America, you will not go and ask the credit from them, they will find you out in few minutes because they will run a match for you on their records.
Make sense?