BUT remember the leeward boat will USUALLY define what proper course is. So if a high pointing boat is sailing up under you; it is THEIR proper course that defines what is Valid; thus if you are sailing a low pointing boat; be ready to tack away. Second; if you are windward boat and disagree with them on proper course; you still have to avoid them and take them too the room;

Finally remember that proper course is something that is REASONABLE and follws the definition of what proper course is (in summary the course you qould sail to get to the mark QUICKEST in the absence of other boats; this MIGHT include sailing to gusts!