Gizmodo reports that iPhone have given their inbuilt camera a really noisy shutter sound in order to thwart male users who enjoy taking illicit 'upskirt' shots of girls on packed subway trains. Apparently this is standard procedure in Japan which still has a big chikan (pervert) problem on the subways. The post was, of course, followed up by lots of comments on how to disable the noise from enterprising otaku.
As an interesting side note, my favourite Japanese photographer, Nobuyoshi Araki, made a great candid camera book about Tokyo's subways called Subway Love. Between 1963 and 1972, he took pictures of people on his journey to and from work. He's got a real talent for snapping people in their most unguarded moments and, of course, being Japan's number one perv, for taking pics of loads of pretty girls (though no upskirt shots here). While doing the book he got into loads of scrapes with Tokyo's transport police and loved every minute of it.