I agree with you, but just to put the other side.
It is a requirement to check Notams. The minimum requirement is to phone up and listen to the recording (not all have access to computers). I suspect your Notam was a nav warning, so would not have made the recording.
Your airfiald does not have an ATZ, so no requirement to make a radio call. Our intrepid three may have followed the rules and been totally unaware of your event, and if not local, thought you were just another unlicensed strip.
Rod1