“doesn't even bother to check NOTAMs is not really a valid defence amongst pilots”
Just to clarify. It is compulsory to check Notams. There is a Tel number with a recorded message, which is accepted as “having checked Notams”. The aero event was not considered important (no RA(T)) so was not included in the message. Our three may have checked Notams and been totally unaware of the aeros event. The airfield is an unlicensed strip so no ATZ and no requirement to call them.
If I was holding an event in class G airspace with no ATZ I would want a RA(T) or I would be very nervous indeed. I would want a risk assessment, and I would probably put observers around the area to spot and report traffic to the competition. Otherwise I would run the risk of “endangering an aircraft”.
That is the way the system works, we may all think it is broken, but that is another story.
Rod1