CRA considers that it still is not required to give notice of its determination to register a taxpayer for GST purposes

New ss. 241(1.3) to (1.5) of the ETA contemplate that CRA can register a person whom it suspects of being required to be registered for GST purposes after giving 60 days’ notice, but with the effective date of the registration to be no earlier than 60 days after giving such notice. CRA considers that these provisions do not interfere with its current practice of simply assigning a GST/HST registration number to someone who should have been registered, and then assessing the person under that number for unremitted net tax – and notes that “CRA could still assess that person under paragraph 296(1)(a) of the ETA for unremitted net tax in respect of reporting periods prior to that person’s effective registration date.”

CRA also acknowledges that when the taxpayer is registered, it generally is entitled to claim input tax credits in its first post-registration return for GST that was previously incurred while it was a registrant (i.e., required to be registered.)

Neal Armstrong. Summary of 26 February 2015 CBA Roundtable, Q. 23 under ETA s. 241(1.5) and of 26 February 2015 CBA Roundtable, Q. 33 under s. 169(1).