I wondered about that too. What's to stop a fielder from just pushing the ball over the fence to keep the runner at third or the batter from getting there? Here are the rules, which don't say anything about whether the deflection is intentional or not: [5.05 - A batter becomes a runner when - ] (8) Any bounding fair ball is deflected by the fielder into the stands, or over or under a fence on fair or foul territory, in which case the batter and all runners shall be entitled to advance two bases; (9) Any fair fly ball is deflected by the fielder into the stands, or over the fence into foul territory, in which case the batter shall be entitled to advance to second base; but if deflected into the stands or over the fence in fair territory, the batter shall be entitled to a home run. However,should such a fair fly be deflected at a point less than 250 feet from home plate, the batter shall be entitled to two bases only.