Lykeion’s Group Banisher (1.0)

What does this addon do?
It helps to solve the long-standing Ghost Group problem in Group Finder. You’ll never again run into a group that’s stuck in a list and can’t be joined. They won’t be shown at all.

How does it work?
Recruitments posted in Group Finder are not timestamped, so the first time you find a group its info and the timestamp will be cached by addon manually. Recruitments are considered valid within 6 hours of the first encounter; recruitments beyond that are treated as a ghost group by the addon and prevented from showing up in the Group Finder. Simple.
Cached groups are purged after 21 days, which should be longer than the interval between routine maintenance.

How to use it?
Install it and it will do the job. No extra UI, no settings menu.