One day while skating at The Cooler I ended up talking to an older man who turned out to be the father of a NHL player (who later played for the Thrashers). We had an interesting conversation, but the thing that really stood out was just how much this NHL dad despised player agents. Called them names like "slim balls" and so forth.
I don't have any personal experience with agents myself, so I can neither confirm nor deny those statements. However, I did stumble across an old article from 2004 which discusses Ilya Kovalchuk's agent Jay Grossman prominently. In this article a rival agency (IMG) accuses Grossman of offering money under the table to Russians to get them to jump to his company. Kovachuk is mentioned as one such example of a player who switched before this draft day.