I've imported pretty much all of my 15 or so GBB mags from Asia without issue...

Look at it this way - buy in Canada, the mags will be about $50 or more plus GST, plus shipping. Buy in Asia (ehobby or redwolf), and the mags are under $35 INCLUDING shipping.. And you'll have them in about the same amount of time as ordering them from A&A.

To me, it doesn't take a rocket scientist to figure that one out...