Next week, the Quebec Court of Appeal will hear argument in the Gun Registry Destruction case: Québec (Procureur général) c. Canada (Procureur général), 2012 QCCS 4202 (unofficial English translation of the first-instance decision).
I have previously explained why the attempted destruction of the data by the federal government is unconstitutional (see my posts here, here and here). Having read the written submissions of both parties to the Court of Appeal, I have some further thoughts.