bjornhall, and others advising arbitrary avoiding action (new acronym AAA) the opposite to the rules,you make my case perfectly.
If a consistent heading of 12 oclock even allowing 30deg isn't developing into a direct head on when the bearing doesn't change from 10 miles,5 miles,3 miles,1 mile,then I hope never to be flying in the same airspace.
Draw it out and see! Then work out what happens if a right turn is made and the other 'craft does nothing,'cos he hasn't seen you or turns right,'cos she has,(ignoring the possibility that its old bjornhall who's going to turn left).
Work out the permutations and you will see that you are certain to avoid by prompt rule-following action. If both 'craft follow the rules even better.
If one 'craft does the opposite to the rule then wham, another statistic.
Lets all just follow the rules,there isn't time to argue even with yourself.
atceng