If you want a license in the US, and even in Canada, it IS important for them to be accredited.  In Canada, there's another acronym, but their system is somewhat parallel in terms of the internship and possibly the exam.

If you already have the equivalent of a U.S. B.Arch. (5 year) and NAAB views it as equivalent after a credentialing agency analyzes it, then the accreditation at the master's level would not matter.  You wouldn't be going into a 2 year program.  You'd probably be going into a 1 year M.Arch. or M.S.Arch., and those are never accredited.  If you are coming with a 4 year bachelor's degree from abroad, and plan to stay, then having your 2+ year M.Arch. be NAAB accredited is very important.  Very few are not accredited, so I don't understand why this would come into play.

Also, I don't know the rules for licensing when a program is skirting either with acquiring, or losing, its accreditation?  I think it's what their status is when you graduate more so than when you start.  If someone knows the protocol on "tenuous" accreditation, chime in, but most schools are accredited for long enough windows of time.