Here are the text of the decisions on the rules issue.
26-1/1 Meaning of "Known or Virtually Certain"
If a ball has been struck towards a water hazard and has not been found, the term "known or virtually certain" indicates the level of confidence that the ball is in the water hazard that is required for the player to proceed under Rule 26-1. A player may not assume that his ball is in a water hazard simply because there is a possibility that the ball may be in the hazard. If it is not known that the ball is in the water hazard, in order for the player to proceed under Rule 26-1 there must be almost no doubt that the ball is in the hazard. Otherwise, a ball that cannot be found must be considered lost outside the hazard and the player must proceed under Rule 27-1.
All available evidence must be taken into account in determining whether knowledge or virtual certainty exists, including any testimony and the physical conditions in the area around the water hazard. For example, if a water hazard is surrounded by a fairway on which a ball could hardly be lost, there exists a greater certainty that the ball is in the hazard than there would be if there were deep rough in the area. Observing a ball splash in a water hazard would not necessarily provide knowledge or virtual certainty as to the location of the ball as sometimes such a ball may skip out of a hazard.
The same principle would apply for a ball that may have been moved by an outside agency (Rule 18-1) or a ball that has not been found and may be in an obstruction (Rule 24-3) or an abnormal ground condition (Rule 25-1c).
26-1/1.3
When is it Necessary to Go Forward to Establish “Virtual
Certainty”?
Q. Rule 26-1 requires there to be “knowledge or virtual certainty”
before proceeding under the provisions of the Rule. In the absence of
“knowledge” that a ball is in a water hazard, is it possible to establish
the existence of “virtual certainty” without going forward to assess the
physical conditions around the water hazard?
A. In the majority of cases, in order for it to be reasonably concluded that
the ball does not lie anywhere outside the water hazard, it is necessary to
go forward to assess the physical conditions around the hazard. However,
there are situations where there will be sufficient evidence that the ball is
in the hazard to establish “virtual certainty” without anyone having to go
forward to review the physical conditions around the hazard.
In the following examples, the conclusion that it is “virtually certain”
that the ball is in the water hazard would be justified without anyone
going forward to the water hazard so that the player would be entitled to
proceed under the provisions of Rule 26-1.
• It is a clear day, with good visibility. A player’s ball is struck towards
a water hazard, which has closely mown grass extending right up to
its margin. The ball is observed to fall out of sight as it approaches the
water hazard but is not seen actually to enter it. From a distance, it can
be seen that there is no golf ball lying on the closely mown grass outside
the hazard and, from both prior experience and a reasonable evaluation
of current course conditions, it is known that the contour of the
ground surrounding the hazard causes balls to enter the hazard. In such
circumstances, it is reasonable for the conclusion to be reached from a
distance that the ball must be in the water hazard.
• It is a clear day, with good visibility. A player’s ball is struck towards
an island putting green. The margin of the water hazard coincides
with the apron of the putting green. Both from prior experience and
a reasonable evaluation of current course conditions, it is understood
that any ball that comes to rest on the apron or the putting green
will be visible from where the stroke was made. In this instance, the
ball is observed to land on the putting green and roll out of sight. It is
therefore concluded that the ball has carried over the green and into
the water hazard. The player drops a ball in a dropping zone in front of
the hazard, which has been provided by the Committee as an additional
option to those under Rule 26-1, and plays to the green. When he
arrives at the putting green, he discovers his original ball on the back
apron of the green lying on a sunken sprinkler head. Nonetheless, in the
circumstances, it was reasonable for the conclusion to be reached from
where the ball was last played that the ball must be in the water hazard.
In the following example, it cannot be established that there is “virtual
certainty” that the ball is in the water hazard without going forward to
assess the area surrounding the hazard.
• It is a clear day, with good visibility. A player’s ball is struck towards a
water hazard, which has closely mown grass extending right up to its
margin. The ball is observed travelling in the direction of the water
hazard and it is known from prior experience that, with normal turf
conditions, the ball would undoubtedly go into the water hazard.
However, on this day, the fairways are wet and therefore it is possible
that the ball could have embedded in the fairway and thus might not be
in the water hazard. (New)