"It is the Zig zagging bit that is the problem for the Mobo to anticipate.
The mobo tends to carry on his collision course because he expects sooner or latter there could be a zig (or a zag ) due, so there is no point in altering course until closer.
What is the difficult bit from the mobos point of view is ascertaining which Zigs are natural ones and which Zigs are collision avoidance ones caused by the mobos selfishness.
(same applies with the zags)
As mobos dont zig or zag it would be prudent for yachts to zig and zag away first because they know exactly where the mobo is going".