I think there''s a lot in the rules that is subjective (for instance, definitions like "keep clear" and "room" and "seamanlike manner" are all subjective; they are interpreted differently based on judgement). This is really unavoidable, and why the rules are an imperfect tool.
You can find situations where two skippers know the rules and both think they are in the right in their actions on any race course in the country; it''s not limited to rule 17 by any means. For instance, I think I''m fetching a mark and someone on port tack comes to the mark and crosses and tacks on top of me. They will feel that the rule about tacking at the mark doesn''t apply to me because they don''t believe I can fetch the mark. So much does depend on subjective interpretations. If you can come up with rules that don''t rely on subjectivity, forward them to the IYRA and they''ll give you a lifetime award and put you in the hall of fame. If you think there are specific ways they can improve on a particular rule (like rule 17), let them know.
If I understand the evolution of rule 17, this replaced the old rule using "mast abeam" where a leeward boat was allowed to luff "as she pleases" and didn''t have any obligation to avoid contact (talk about a license to ram!). It was a confusing rule (the mast abeam part, anyway) that was considered to allow/encourage aggressive luffing battles downwind, so the rules modifications in 1997 strengthened prohibitions against contact and took out the "mast abeam" and "luff as she pleases" language.
Maybe modern electronics offer the only way to take some of the "subjectivity" out of interpreting and applying these rules; we could have on board computers and sensors that could indicate when a boat was sailing "above" her proper course based on wind direction, compass
heading, VMG, etc. and set off a flashing red light that gives you five seconds to alter course or incur a penalty. But if we do this, we take away the opportunity for competitors to exhibit (or fail to exhibit) good sportsmanship and engage in fair play. A big part of this, in my subjective judgement, is to presume that the other boat''s skipper is trying her best to abide by the rules and is not trying to take advantage of them. Unless I see clear evidence to the contrary, I assume that when a skipper says she is sailing her proper course, I accept that and deal with it. If I get sidetracked into worrying about what an "objective" observer would think about who''s sailing proper course and who isn''t, I''m going to lose my focus anyway.
Racing or other competition can certainly bring out the worst in some folks; we''ve all seen skippers out there who try to use their knowledge of the rules (or others'' ignorance of them) to their advantage. I like to remember that it can also bring out the good in some folks, who do their best to know the rules, take their lumps when they''ve broken a rule, and remain on friendly terms with the people they compete with after the race. Call me Capt. Polyanna. Just don''t try to barge at the start!