As I say, I exempt associations from this. If someone is going to join a consultant lobby firm, they should have some cooling-off period. It's at the political level that these people operate, which is where political relationships come in. If somebody goes from an association to an association, they tend to deal mostly with sector-specific issues. So to answer your question, three years is a little less of an intrusion into somebody's career.
Also, one point that I didn't make in my presentation is that you have a process in a democratic system of parties. They operate on a partisan basis with people who have been partisan all their lives. If you take that five-year chunk out of their careers, you're going to have a real breakdown in the party process, I feel. Those people started out doing the grunt jobs--no offence--with MPs and so on. They worked themselves up, and they want to cash in on it. It happens all over the world.
So three years would be fine, but five, I think, is too long.