Mostly this problem is contained in the fact that the US makes it so difficult for Canadians to get green cards (you heard it here), but if an American orchestra really wants a player, they have their ways.

John / The Knights released by Ancalagon Records Winner 2011 Juno Classical Album of the Year - Large Ensemble or Soloist(s) with Large Ensemble Accompaniment
2011 — Bach Sonatas: Lara St. In 1976 at five years old Lara St. John began making frequent trips with her mother and brother to Cleveland Ohio where the young St. John was free to make artistic choices that were no longer driven by commercial considerations.

Lara St. John (born on April 15 1971 in London Ontario) is a Canadian violinist.