When there's no test available for the drug being taken (a la epo in 1999), it's kind of hard to get an A and B sample to test positive. Yes, Marion was clean too, I mean she never tested positive :-)If it looks like a duck, quacks like a duck, and walks like a duck, it's probably a duck. For duck read drug-taker.
Wake up man and stop believing the bullshit. Read From Lance to Landis before responding, and realise it's written by two well-respected journalists who have a history of uncovering drug cheats, and who would be unwilling to risk their career and reputations on something they didn't know was true.