Here is what WS 2017 Judges Manual says regarding this matter
"K.22 Onus of Satisfying the Protest Committee
For protest hearings, the burden of proof is the “balance of probability”, unless
a rule specifies a different burden of proof.
There is one rule, 18.2(e), that permits the protest committee, when there is a
reasonable doubt, to presume facts about whether a boat obtained or broke an
overlap in time. However, the protest committee must not merely rely on this
rule; it must take an active part in trying to resolve the doubt by other means. It
should question the parties and witnesses to elicit all available evidence to find
facts and to learn what actually happened. Then, if still in doubt, it may use rule
18.2(e) to resolve the protest.
When making its decision, rule 18.2(e) is relevant only when the protest
committee is in doubt. In this case, the decision might use such words as: ‘The
protest committee is not satisfied that A, astern established an inside overlap
before B ahead reached the zone,’ and cite rule 18.2(e). When the protest
committee is satisfied by the evidence that A astern failed to obtain an overlap,
then the words used might be: ‘A astern failed to establish an inside overlap
[etc.],’ and rule 18.2(e) would not be cited in the decision."