Just as a personal statement, I believe that an amnesty would be a good way to go. This is a personal view. If you're going to punish to the greatest extent of the law, then given that someone has broken the law, what's the point of the person voluntarily disclosing it if the person knows he or she is going to be found out? The person has broken the law, so the person may as well continue to try to evade, and as you increase your enforcement, the person is just going to dig in deeper or go to another jurisdiction or something.
In my personal view, I actually believe that some kind of amnesty would be a good way to start to bring people back into the fold and not make it so onerous on them, that given that they have broken the law, they can never recover.
If I may quickly add one more comment about Revenue Canada, I don't know the distribution of careers within the organization, but my guess would be that there are probably too many accountants and lawyers going after enforcement and not enough economists trying to create incentives so that, as my colleague in Montreal put it, people are not tempted to do this in the first place.