Things you find in other people's books

On a weekend visit to Harrogate last month I bought a couple of novels in a charity shop. Opening one of the novels I found this tucked inside the pages. It's an unused ticket to a Burnley v Bradford football game from March 8, 2003. I think I've found someone's disappointment of a missed game - or could it have been hidden there deliberately? Is it yours? Want it back?