Here we go again..
Some more thoughts :
1 NM offs et is fine in RNP 10 Airspace or higher. In RNP 5, 4 or in TMAs this is too much, but as in nearly all FMS you only can manually off set full digits, it is not possible to off set less than one full mile.
Only solution would be enbedded off set.
The more the Navigation accuracy of your aircraft, the least ammount of offset you need. In fact with GPS/IRS 0,1 NM will do.
To avoid the problem encountered in the begining of this thread, the notion of applying RANDOM offset between 0, 1 and 0,4 NM would elimaniate that problem.
Problem is when do you revert to accurate NAV . 10.000 Ft as suggested won't work as there are may airports above 10.000 Ft...
Most collisions occur in low altitudes anyway...in TMAs or close to airports, . this question at the moment is a choking point,
Last : Mathematically, someone in the ICAO Working group demonstrated that if you offset, on multiple crossing points, the area of exposure to collision is greater, therefore the risk of collision is higher.(But do not ask me to give you back the formula )For this reason , legally ICAO cannot implement a measure that will increase the risk.At least this is the reason they give us. Common semse might prevail one day, but like many things in aviation, it will need a few more collisions.