It is silly until you realize that you may not sight all launches, and you have to depend on your sensors.
IMO it is a silly and risky way of assessing enemy missile capabilities - you 'defeat' every brief out of kill-zone non-launch and then are hit by the first pair of real missiles... yet can still claim that hit rate is less than 10% or some such nonsense... even saying that 50% is 'correct' based on one hit from a pair of missiles misses the point that this is one hit from one engagement.
