In many sports, players will often find that there's some little thing they can do that has a massive impact for lucky fans they encounter.
In baseball, players will sometimes chuck foul balls that don't make it into the stands to eager spectators, especially if the one they're throwing it to happens to be a child.
Unfortunately, some people are so excited about a ball coming their way that they either don't notice the kid or dismiss them before snatching it themselves. It's not a popular thing to do, but people still do it.
And based on what's been going on at the French Open lately, it seems that tennis isn't immune to this problem either.