It is perhaps unsurprising to learn that Dalrymple voluntarily picks up litter from around his local hospital, and even less so that he finds a deeper meaning in its contents:
Among the most frequently encountered items were used car-park tickets. It would be an interesting experiment to compare the rate at which they were discarded before and after they were inscribed with the registration numbers of the cars on the tickets. In my career as a volunteer litter-picker, I have rarely come across a piece of litter that could be traced back to a litterer.