Reasonable Evidence?
By Gary Hill - RCGA Rules Official

When there can be no clear determination of the facts, the Rules state the procedure to be followed. In the case of a ball moving after the player has addressed it, the player is deemed to have moved the ball regardless of whether or not he caused it to move.

In other situations, the Rules provide that "reasonable evidence" shall be used to reach a conclusion where the facts cannot be known. For example, a splash does not prove your ball is in the water hazard. Was a high wedge shot hit into a large lake or was a driver skipped across a narrow creek? Reasonable evidence must be taken into account.

I cannot give you a precise definition of reasonable evidence. It is purposely and necessarily broad as to permit sensible judgments to be reached on the basis of all the relevant circumstances of particular cases. However, you may be surprised to learn that the commonly claimed "might be" or "could be" in the water hazard is not sufficient. Reasonable evidence is sometimes referred to as the "Ivory Snow Rule" (you may have to ask your grandfather about these commercials). This means that 99 and 44/100 percent of the evidence has to be in your favor.

Here is a good rule of thumb: If you are searching for your ball in a water hazard AND in the area around the water hazard, then the searching of the area outside the hazard prohibits you from claiming the ball "must" be in the hazard.

The Rules consider only what is KNOWN within five minutes of searching or what is KNOWN up to the time the player puts another ball into play. It is irrelevant, from a rules point of view, where the ball is ACTUALLY found at some later time or date.
Food for thought: If 99.9% accuracy is good enough, 12 parents will be given the wrong baby today.