The first thing I will say is that I am not a national security expert. I know my registry. That's it.
Having looked a bit, having sat on panels with individuals who deal with the American registry and having looked at the Australian registry, I think there would be an advantage to communicating with those individuals to see what the pros and the cons of their registries are. I have heard that in the U.S., for example, it speaks of “agent”, while in Australia, we're talking about “activities”, even activities that are trying to influence Canadians.
There is good in those registries that exist, and I think it would be good for anyone to study them, but I'm certainly not the expert.