Under the Rules of Golf, it is up to the player and his partner to determine where the ball last crossed.
"Without definitive evidence, the point where Woods' ball last crossed the lateral water hazard is determined through best judgment by Woods and his fellow competitor. If that point later proves to be a wrong point (through television or other means), the player is not penalized by Rule 26-1 given the fact that a competitor would risk incurring a penalty every time he makes an honest judgment as to the point where his ball last crosses a water-hazard margin and that judgment subsequently proves incorrect (Decision 26-1/17)."
Tiger turned away and probably didn't see where it crossed. I'm sure Joey LaCava had eyes on it, and his playing partner, Casey Wittenberg, definitely saw it:
"I saw it perfectly off the tee. I told him exactly where I thought it crossed, and we all agreed, so he's definitely great on that. There is no doubt, guys. The ball crossed where he dropped."
A Rules Official wouldn't have helped the situation. The "overhead" camera was from a very deceiving angle. The best angle is the one the player and his partner has.
With where the ball landed and hitting a high hook, this might be a more realistic view of what it looked like:
