Judges, prosecutors and journalists all know that collusion happens every day. As I noted last year:
Bernie Madoff's Ponzi scheme was a conspiracy. The heads of Enron were found guilty of conspiracy, as was the head of Adelphia. Numerous lower-level government officials have been found guilty of conspiracy. See this, this, this, this and this.
Time Magazine's financial columnist Justin Fox writes:
Some financial market conspiracies are real ...Indeed, conspiracies are so common that judges are trained to look at conspiracy allegations as just another legal claim to be disproven or proven by the evidence.
Most good investigative reporters are conspiracy theorists, by the way.