Managing Your Land
Every griefer attack is a reminder that many land owners aren't familiar with how to set parcel land security settings to prevent issues.
CL does NOT return prims for being over limit Group owned vs. Set to group Best practices for minimum griefing
It is always recommended to set autoreturn, which will return objects not belonging to the land owner or group members after a certain period of time.
As an example, most sandboxes set an autoreturn time, usually around 3 hours.