Indeed. 'Contamination' seems to be the defence du jour in ITF hearings.
Like the recent case of Sara Errani who blamed her ingestion of a prohibited substance - letrozole, which can increase body mass - on the fact that her mother's letrozole pills, which she was taking for breast cancer, had contaminated the food she was cooking because they had been in the same kitchen cupboard, which is quite amazing because said pills were in a packet, and the food probably wrapped up or in a container. She got away with a two month ban, which has just ended, because the tribunal decided that (a) letrozole was more likely to be more helpful to male body builders, and (b) that the amount was too small to have been of significant use anyway.
All I can say about Dan is that he's the one who'll have to live with his conscience if in fact he has been less than economical with the truth.