Rowling Steps In
In an interview with David Heyman, MTV got him to make a slip, on something Jo had to told them: ''You know, I wouldn't do that if I were you. Or you can, but if you get to make a seventh film, you'll be tied in knots.'"
Now, what exactly was said will Not be put here, but should you want to know what character she WAS speaking of, feel free to check it out in the MTV Movie Blog interview, found HERE.
But be warned, as you see in the above statement, it IS a spoiler about book #7!