I found this court case which I believe supports my claim.
Scuttlebutt News Center: Defining Liability Between Racing Yachts
Thus this court ignored the International Jury's findings, and turned to the COLREGS: Charles Jourdain was the overtaking yacht and obliged to keep clear, though the court found both yachts at fault (60% Charles Jourdain and 40% Endeavour).
The point here is that if the Colregs were the controlling law, the overtaking boat has to keep clear.
It is interesting that the windward boat was still assessed 40% not 0% which is very common as the court figures it takes two to tango and while the colregs say the overtaking boat has to keep clear the skipper of the stand-on vessel is obligated to not participate in a collision and he could have seen it coming and headed up apparently.
The case was appealed and the racing rules were finally used to adjudicate the collision and apparently the windward boat was assessed a much higher penalty.
So the lesson is that as cruisers we have to remember that the Americas Cup participants are following different rules from the ones we have to follow.