Nothing has changed as far as the rules from the IRS. EXCEPT it is niow easier for them to nail cheaters. They have always had the option of turning away Canadians suspected of over spending time in the USA. They really do not have to check any shared information. If the fellow at US customs dos not like you he can simply send you back because he thinks you will be staying in the USA. That form has ben around for years. Canadians who follow the rules have no worries. Interseting that the net is full of articles on this subject lately. Almost all of the stories come out of BC!!!
Moisheh