^I suggest you rectify the oversight as soon as possible.
Here's an idea; not perfect, but it might do. Let me know how it sounds.
Set an invisible mission with an "observe Reaver vessel" goal. Every time you land, this mission would be aborted and restarted. Upon ShipGoal completion, start another mission with no goal, but a "fail if boarded" flag. This mission would be aborted automatically every day by a cron.
Here's the key point....does the date ever advance when you're just flying around, not hyperspacing or landing?
Also, another sticking point is that random Reaver ships wouldn't count as completing the ShipGoal; it'd have to be the mission-specific ship. Any ideas on how to get around this would be welcome.