My conjecture is that McCain will be doing well publicized "purges" like the one mentioned, periodically until the election. This will allow him to be seen acting on his "principles" (ie not being in bed with lobbyist) by ridding his campaign of lobbyists, while not actually having any "principles" (ie being totally in the bag vis a vis K Street). No doubt he can afford to toss a few overboard every few weeks without running short of volunteers.