if you look at risk of collision and RTL then you could argue that every time 2 seperate aircraft get airborne there is a RTL and risk of collision!
Not really. Both the MAA and CAA use "Bow Tie" to assess risk. The Hazard, as defined by both, is aircraft operations in Class G airspace. A RtL incident is created when there is loss of control of the Hazard, the MAA indicate that as being an AirProx, and the MAA as being "aircraft in close proximity of another aircraft that their safety is compromised" - Airprox?
So it could be argued that there is a RtL for every Airprox, but I limited it to Class A.
By the way, RA 1210 states that "near misses" should be taken into consideration when assessing risk.
DV