“Imperils the privacy of up to a million Canadians and creates a two-tier level of citizenship in this country, discriminating against citizens based on their ethnic origin. It could include so-called border babies, Canadians whose mothers gave birth across the border for medical reasons; Canadians who have returned after holding green cards for work in the U.S.; Canadian snowbirds who could be deemed ‘U.S. persons’ based on the length of their stay in the sun; and Canadians born to a U.S. parent who may have never set foot in the U.S. If you are a Canadian holding a joint account with a U.S.-born spouse, your financial information, too, could be headed to the files of the IRS — and perhaps beyond.”
http://www.thestar.com/news/canada/2014/05/25/us_tax_deal_jeopardizes_canadians_privacy_harper.html