Dick
My problem is that you presented the issue as if there NO mitigating factors in place.
As a qualified CIR and IFR-current pilot I am quite happy to encounter a rainshower on the threshold! Aren't you? There's approach minima that include visibility for a reason (BTW, a UNICOM guy/gal in any of the aviation businesses in Ballina can't see the threshold of RWY 24 and if they're sitting in an office doing the Unicom on top of their real job, they can't see the runway at all. )
As for the aircraft on the wrong frequency or doing the wrong thing - I've seen "bad/poor behaviour" and errors made in controlled airspace as well - you've got to keep your wits about you - I've been given turn instructions in Cairns that would have put me into Mt Whitfield and seen ultralight aircraft plough on through controlled airspace undetected. The YAYE radio call incident with an RPT is pretty bloody rare. You may as well take the example of aircraft debris falling to the ground occasionally and mandate we all live under concrete shelters, just in case....
Have a look at this:
Unicom Responsibility Who's Running The Radio? - Flight Training and see if it solves the non-problem for you.