During the preparation for one of the winter presentations I've given, some thought went into rule 18.2 Giving Mark-Room. Specifically on the order it is used.
From the view-point of the sailor the way this rules is used is different then the order it is written in the rule book. Most sailors start with 18.2(b): What is my position when I or my opponent reach the zone.
Am I inside boat? Then I have mark-room.
Am I clear ahead? Again, then I have mark-room.
That are the first questions asked approaching a mark.
If there's doubt on that position most sailors (should) use 18.2(d) and determine their rights according to how that doubt is resolved. I.e. was the overlap long standing and only (doubtfully) broken at the very last minute or vice versa.
Then they use 18.2(c). It tells them what to do even when the overlap is broken or a new overlap begins.
Only if these first three are not applicable sailors go to rule 18.2(a). That's the basic principle stating that an outside overlapped boat shall give mark-room. For the rule-makers/writers it is the first (most important) rule, but not for the sailors.
And finally they have to use 18.2(e). If - from the moment the overlap began - they are unable to give mark-room, they are not required to give it.
From 18.2 (b) to 18.2 (d) and 18.2 (c)
Then 18.2 (a) and finally 18.2 (e)
Is this difference in use, something rule-makers should consider when revising rule 18.2 in the future?