The bronycon hambeast claimed that he was pretty self conscious about body odor (probably because of years of trolls talking about him stinking, wich was probably true back in the day) and visited the bathroom often to clean himself of sweat and such. I think Marvin said also that he doesn't (usually) stink either, so the other probabilities are:
-It's just bullshit
-The classic blue and red developed some kind of permament stink because of being rotten
-Being a con, there is a fair chance that the
fragance was coming from some other unwashed nerd nearby
-The ages-old debate: Did Chris

from the shock? (I know people tend to downplay this, but he did drop the bomb over pretty minor stuff back in the day, like
recalling some very mild bulling from ages ago)