I often run alone, but had a very odd encounter with a chap on a bike on Sunday, who insisted on cycling next to me for about five minutes, while he put the world to rights. Nothing threatening about him, but it was very strange. Monday, I was running a 12 mile route which partly involved going down a public footpath along a golf course, and elderly gentlemen firing golf balls at me without warning. As a female runner training for the New York marathon in November I do have to get the miles in, but I will admit you can feel a little vulnerable at times (especially as I'm no Paula Radcliffe).
Good luck with your 10k, don't let other people put you off!