Time for a Federal 20% witholding tax on ALL monies that flow across the Canadian border, regardless of their source or whether they are in cash, gold, etransfer or wired form. 

Until the individual can prove the money in question was legitimately filed in a CRA tax return, the government should keep the 20%. This would be easier to administer and wouldn't open Canada to any accusations of 'racism' re foregin nationals and the Charter.