The quadrantal rule does not provide any separation. It is simply an orderly system that can remove some possible conflictions but you can till have an aircraft approaching you at the same level..........from behind, from the left from the right and also from directly ahead!
I will bite ... how can you have an aircraft approach you from directly ahead (i.e. reciprocal) at the same level if you both follow the quadrantal rule ??
- and that is just the IFR ones who are complying with the quadrantal rule. Add in the VFR flights who ignore the rule and you will see that quadrantal rule and separation should not be used in the same sentence.
VFR traffic is not ignoring the rule ... it does not apply to VFR aircraft therefore how can they ignore something there is no need to comply with
