Found this on a train this afternoon:
I’m guessing a bookmark that’s been sitting inside someone’s book for fifteen years and they decided to re-read the book, and subsequently left it behind on a seat.
These scratch tickets were used before Metcard was introduced in the late-90s, and were notorious for fare evasion. They didn’t indicate a year (so some people went to the trouble of keeping them and using them on the same day each year). And because they were self-validated, some people kept them unscratched and only scratched them when they saw ticket inspectors.