Slightly different but I used to work in a supermarket and I would often have to tell customers not to flip their wallet completely open and leave it when they got their store card out. They would have their driving licence in the front with their full name, address and date of birth, quite often their card PIN written down in there, and other personal information which they would lay down on the counter while they faffed about swiping their card, for anyone with ill intent to take a furtive photo of or just memorise.
I would know which of my customers were having regular medical treatment as they'd have their appointment card from the doctor visible, quite often a medical card which said what treatment they were having (if it needed to be quickly available in the event of a collapse). We all carry a lot of personal information on us, and need to remember how little it can take for someone to copy and steal at least part of your identity.