Thanks for the question.
I think the point I was making is that if you can agree on what the objective of the legislation is, then work backwards: who is caught or where does the Canadian society benefit from transparency? Again, I think the point I was trying to make is that for anybody who is, in any kind of organized way--apart from the citizen-MP relationship--participating in a public policy debate, I think you can make the assumption that they're doing it in their self-interest. To simply use “paid” as the bar...you are having a lot of people who are influencing a considerable amount of pressure on that process and who are completely outside this regime.
So by putting the definition as “communication with decision-makers to affect outcomes”, everybody understands what we're talking about now. If you take out “paid”, then it's just the case that everybody who's going to play in that sandbox has to register and has to follow the same rules.