Pretend that you are playing #17 or #18 at Mountain Creek where there are water hazards to the right of the holes, but not visible from the tee. You hit drives towards those areas but you cannot find your ball. Is the ball LOST, or is it in the hazard(s)?

What reasonable evidence does one need to be able to proceed under the water hazard rule?

Decision 26-1/1 is purposefully vague in its description of what reasonable evidence is and I was wondering if someone had come across something more definitive. I had a brief discussion with two Level 3 officials yesterday but still could get an exact answer.