Except for RRS 18.2(d), the rules do not place any onus on either boat. It is up to the protest committee to find the facts. Protest committees will often be more sympathetic to testimony from the protestor, but there is no burden of proof on the protestee. In the event of conflicting testimony, PC will often side with whomever had a better view of the incident. PC is much more likely to accept tangible data (knots, degrees, seconds) than vague statements ("too close").

Regards,
Eric