Snape sighed. "There's no such thing as a perfect defense," he said. Quoting a textbook, probably, the prat. "In exchange for such strong wards, they had to leave a whole side open. That's not to say one can fly in, but if you're willing to travel at ground level through the Forbidden Forest, then you can conceivably come and go as you please. The Founders made the Forest so deadly by design. I don't believe anyone's ever successfully utilized the flaw, though."