[godshatter]

Not sure about conferences, but for cruise ships buffets would be my guess. Most people on cruise ships eat at least a few meals at an overcrowded buffet. Multiple people touching serving utensils, stacks of plates, fishing for silverware, etc. Not to mention sneezing around open food containers.

[dboreham]

I got the impression people were still being infected on the Diamond Princess after they were confined to their cabins.