In baseball, is it ALWAYS interference when the runner collides with a fielder attempting to catch a ball?

I saw this today in a Babe Ruth baseball game: The first baseman settled under a lazy pop fly about three feet to the home plate side of first base and also a couple of feet into foul territory, and stood there under the ball. Just as the runner approached first base (the runner was taking an open, straight line route to first base right along the foul line), the fielder suddenly moved to his right into the direct path of the runner (perhaps because the wind had drifted the flight of the popup), and the two men collided right on the foul line just before the ball came down. The ball dropped and the umpire called the runner out (and also ejected the runner for running into the fielder who was trying to make a catch - league rules). Would this same ruling have occurred under major league baseball rules?