That comes from a Mexican Caravan website.
There is more detailed info here:
http://www.bnn.ca/News/2014/3/21/Snowbirds-beware-Days-of-strict-tax-enforcement-are-here.aspxhttp://www.theglobeandmail.com/globe-investor/personal-finance/retirement-rrsps/why-canadas-snowbirds-are-under-us-scrutiny/article22908355/In my case, I spend a lot of time in Mexico, so that decreases my day count in the US. I do however live a km from the US border and frequently cross fro a half hour or so to get fuel, check US mail, etc. Every on of those knocks a day off the count. Scary.
Most Americans are unaffected, not too many head north to escape the heat.