There was a story where like a former (Australian?) prime Minister posted a flight ticket, a guy got all the details from the ticket, could log into the airline, check all flight details and with a little bit of look up in the page details found stuff like Adress, private phone number, credit card info and so on.. Somewhere there is a really detailed blog about what happend up tk the point that the "hacker" got a call with said prime minister to talk about what happend