I think there are a couple of aspects there.
One aspect is this issue of opacity or lack of transparency, of money being held outside the net, if you will, of taxation. Related to that is aggressive tax planning that utilizes these environments. I believe the government has taken a look at the international taxation regime for Canada, which includes the appropriate use of third countries for tax planning. I refer you to the report by Peter Godsoe that is relevant to this issue, but maybe not comprehensive for the issues you're raising.