I definitely think that should be some limitation that are placed in terms of the ability for advocacy groups to lobby Members of Congress. I think that it is important that the Members of Congress can act on their own accord without the influence of outside sources by means of illegal tactics.
Lobbying is not a negative action by default. Anyone talking to the government about what you want to see in the future is actually the definition of lobbying. However, from this simple beginning a massive industry of professional lobbyists has appeared. We should regulate how and when these professionals can use their influence so the playing field is level for the individual.
Lobbyists are not a part of the process of representation. They simply get between a Congress person and his or her constituents, muddying the waters by trying to influence congressional votes. One has to wonder how often a Congress person votes against the best interests of his or her constituents due to the influence of a lobbyist. The lobbyists need to get out of Washington, D.C. so that government can operate as it was designed to by the framers of the Constitution.
If I had my way, there would be no paid lobbyists allowed access to any member of Congress or their staff. These "advocacy groups" have perverted Congress and clogged our legislative branch in more ways than you can imagine. Everyone should have the same level of access and influence on Congress as private citizen.