The thing that Canadians need to understand is that under the Conflict of Interest Act, there are very strict post-employment rules for people who are in a minister's office. You can't change sides.
They will look at someone's situation. You get a letter saying that you can't talk to people you had significant dealings with in that position for a period of one or two years. They also say there is a lifetime prohibition on you using information that you obtained in that position to better yourself.
Those rules already exist. Throwing another set on top and making it a five-year ban may.... People may sleep better at night, but you haven't altered the situation at all.
Bringing those two pieces together, and making sure there is the appropriate authority, is more than enough, really.