My understanding is that temporary or permanent changes or additions to the information in the AIP require a NOTAM. Information regarding anything that may affect the safety, regularity or efficiency of aircraft navigation may be advised by NOTAM.
It doesn't hurt to pass the information and leave it to the AIS to decide whether a NOTAM is appropriate.
I know of occasions where they have chosen not to act on advice of a flour bombing and balloon bursting competition at a local fly-in.