What I'd like to see, that is, if I still watched it, would be the
Mythbusters do a piece on SF's public transportation
system's seats, handholds, floors, etc.
I've seen them do bacteria counts on food dropped on the floor, bathroom samples, [alleged] rat urination on soda cans, etc.
Riding the various lines of BART various times during the day
should give a great statistical sampling to ID what and where
the dirtiest things are that pose a potential health hazard.
Those boys on Mythbusters will need their haz-mat suits for that show.