As I noted before in this thread, I signed an NDA as a beta tester of Windows95 (all those years ago) and Microsoft didn't seem to have a problem with me being swedish then (or in later beta programs).Scott_Rouse said:We are not excluding Canadians (or other non-USA residents for that matter) as we discuss the plans.
The only hitch I can foresee is because testers will be asked to sign a confidentiality agreement I am not sure how it would work with people outside the USA.
An agreement is an agreement. When I signed contracts with TSR in the 80-ies, I didn't have to pledge my first-born just because I was a foreigner (which would have been very strange, since those were foreigns distribution contracts).

In the end, no NDA is equal to a +5 plate armour unless there is some trust between the involved parties. Obviously you'll have to pick playtesters among people you can trust. We'll just have to wait and see where that trust will land.