I remember mentioning that I'm a Canadian student to whomever I spoke on the phone with from SpaceX, and they said no, but I don't know if they knew about this exemption, or if SpaceX is just generally very broad in this regard to make things easier.
I think what is being discussed is a TN Visa for Canadian citizens. Generally, it is very easy for any Canadian to come work in the U.S. as they just need to go to the boarder to have some paperwork signed off for their TN Visa. But, the problem with SpaceX is that we have to follow ITAR Regulations and can only employ permanent residents (U.S. Citizens and Green Card Holders). TN Visa Holders unfortunately do not fall within either of those groups. If anyone is interested in working at SpaceX, then definitely apply or contact me. Cheers!