I think I know the answer to this but I'll put it out there.

11th hole at King's Forest. Hitting from an elevated tee deck down into "the valley". Creek, marked yellow stakes, runs across the fairway (actually, just before the fairway even starts), and is out of sight from the tee deck. Trees both left and right. Golfer slices hard right, and the ball drops out of sight. Ball is never found.

My playing partner was adament that he could drop and play a ball at the point where the ball crossed the hazard, assuming because the ball was never found, it must be in the hazard.

I'm pretty sure I read elsewhere on here that you cannot assume the ball finished in the hazard if you didn't see it land in the hazard. Therefore, it is treated as a lost ball unless it's otherwise found. If it's found in the hazard, then it's played as a regular hazard shot. But the correct ruling should have been a lost ball, and to play a provisional off the tee. Correct?