I think the primary objective is trust and integrity. It's so that people can believe there's not a revolving door.
I think there's a two-barrelled answer to that question. One, there should not be a revolving door. Two, people need to believe that people aren't trading on their networks in their life post holding public office. I think a really long period would be too punitive. A very short one would be too short. Less than two years, I would imagine, would be too short.
I would say that five years is getting on the longish side, but again, I don't think that's for the regulator to say.