A common problem is the "Out Of Date LM". I just had an awkward situation with that: I used a seasonal LM, and the first things that rezzed were seasonal decorations, but when everything finally rezzed: I had TPed into a private residence. And they were home. Very, very awkward.

Whenever the topic of killing off "dead LMs" comes up, it is pointed out that it would require a search of everyone's inventory, be very computationally expensive, etc. Very valid concerns.

I would like to propose a different mechanism: the region or parcel owner may set an "Expire Old LMs" property on their land (perhaps for a nominal fee, if overuse is a concern for some reason?) that sets to the current date and time.

When someone uses an LM, have it check for the presence of that date, and if the LM was created that timestamp, the TP fails and the Resident is noted that their LM has "expired". At which point, several possible outcomes.

1) The LM is moved to Trash.

2) The LM just "poofs", is removed entirely. (I can see both sides of the argument on this one.)

3) The LM is moved to an "Expired Landmarks" folder.

4) Nothing is done to the LM, the Resident has to deal with it manually. (Which will just lead to repeated attempts, tbh.)

This removes the massive-inventory-search problem: it is comparing two properties at the time of use, and the thousands of LMs sitting idle in the inventory DB don't get bothered at all. It would reduce the incidence of "Hey, you just TPed into my house!" and "Didn't this used to be a club?"

When land is abandoned, I would have the date set automatically.