If the 402 was cleared for the ILS then there should have been no conflicting traffic period,
Amazed how you can state that
Outside of CAS, then anybody can do what they like, and if you are there, then the rules are "see and be seen" - whether in an LAA homebuilt, or a 747.
I fly from an LAA homebuilt, to an ex-military Jet, ex-Eastern Bloc trainers and public transport airliners. Each have their own "risks", which differ considerably, both for me, and my colleagues / passengers / other airspace users. I do trust others also (apart from the passengers), understand those risks.... and the tragic events of Sunday are hardly unexpected, unique, or unlikely to be repeated. If you want to minimise the risks, then please understand that short of full Radar Control, in CAS, your best defence (but not absolute), is to have your eyes and ears "outside" 80+% of the time. But there's still the 20% or so when it's just not your day...
NoD