There are plenty of other mitigations that could be applied to reduce the risk of fast jet mid-air collision, some of or all of which fail the 'reasonableness' test for various reasons:
- Establish controlled airspace around all military airfields
- Mandate use of Traffic Service as absolute minimum level of service outside controlled airspace
- Limit autonomous military training to Restricted or Danger Areas
- Paint all combat aircraft black
- Extend danger areas around weapons ranges to include all maneouevring airspace, not just the weapon flight airspace
- Apply the 250kt below 10000ft speed limit
and there are probably more. AOC 1 Gp could have demanded any or all of these (well, apart from the first - he probably would have had a fight on his hands). Is he negligent for not doing so? No, none are reasonably practicable. DV, your 'reasonableness' radar is a bit out on this one. A risk event occurring does not change anything in terms of the prescribed treatment, unless the number of occurrences invalidates the probability of occurrence assumed in that treatment. If it was declared ALARP following approval of CWS funding, it's still ALARP after the collision, unless the underpinning maths has changed.
Incidentally, at least one of the 'Cat A Tornado airproxes' being bandied around in the Scottish press was a Tornado minding its own business behind a tanker at night when a Typhoon pilot got horribly disoriented and nearly clapped hands with it. Hardly fair to blame that on the Tornado or its lack of a CWS, I would say (TCAS would have been off in any case).