The presence of other boats with ROW - including, but not only Yellow - affects Red's course to clear the finish marks.

Great news - World Sailing has issued the corrections including this item..

Visit

to download both the 2025-2028 RRS with corrections and the detailed document listing the specific changes.

John

Well, I think my point is that the rule can't require Blue to have a crystal ball and know whether or not she can in fact successfully pass Yellow (or an arbitrary obstruction).  That is something that is only knowable when/after it actually happens.  That's why my feeling is that "... may choose to pass an obstruction on her port or starboard side" is really about "choosing" which side (port or starboard) to try to take/pass/avoid the obstruction and not about attempting to pass and succeeding, attempting to pass and failing, attempting to pass and no hope of actually passing, or just avoiding, etc. 

(and as Jim notes, Blue's proper course could certainly be ANY reasonable path around Yellow)

When we decide on breaches and do not believe the competitors fully understand the definition or advice.

It is what happens not what they say.

Ben ... I think there is a new MR Call .. or maybe it was a Rapid Response .. where they discuss, in the context of RRS 16, the concept of a KC boat 'not being able be given room to continue to keep-clear, if the KC was not keeping clear when RRS 16 initially applies.

The reason I bring this up in this context is to possibly frame this in the context of RRS 16 and how Case 50 creates a reasonable timespan of action between RRS 16 and RRS 14.

From RRS 16's POV
Each time a ROW boat changes course, she shall give the KC boat room to KC.  When the KC boat is in an obvious state of KC'ing (let's say P/S .. > 6 BL's apart  ... bow-to-bow course intersection), each time the ROW alters course, there is a reset opportunity for KC to 'continue to KC'.

From RRS 14's POV
A ROW boat need not act to avoid contact "until it is clear" that the KC is not keeping clear.  Rhetorically, RRS 14's "when it is clear" is a single moment in time at which time the ROW boat must act in the time-rhelm of "reasonable possibility".  At that point of time of action, the KC boat assumably is not in a state of keeping clear.  If ROW's action to avoid contact with an KC boat that is not keeping clear involves changing course,  that change of course doesn't effectively create new RRS 16 KC room entitlements to the KC boat already in a state of not keeping clear.  

So, Case 50 spans the space between "Clearly KC'ing" .. where RRS 16 provides new room to KC with a course change by ROW .. and "Clearly NOT keeping clear" where the ROW boat's actions may be too late to avoid contact.