As someone who does check NOTAMs and plan accordingly, I've been rather frustrated in the past by the number of NOTAMed events thaat have clearly been canceled, some at a relatively early stage, and yet no one has bothered to cancel or amend the NOTAM.
The military are generally very good at this, releasing airspace back to civil use where an activity finishes early or is cancelled.
Maybe AIS need to get other NOTAM filers to adopt the same principles.