This feature request is for the llRezObjectWithParams() constant, REZ_FLAG_DIE_ON_NO_REZZER.
Objects rezzed with this flag auto-die when the rezzer dies or leaves the region.
"Leaves" entails, detached, deleted, returned, region crossed, etc.
This is only handled in root prims that have this flag set and whose rezzer is removed from the region.
Attachments that were previously rezzed then attached are ignored when their rezzer is removed from the region.
There is no background timed check similar to autoreturn needed for this mechanic to work.
It is a one-time check.
Whenever an object key is removed from the server's internal object list, a check of all unattached, root prims in the region that have the same key as rezzer and are set with this flag will, in-turn, cause those objects to be removed from the internal object list.
This status is meant to compliment the recently filed feature request for llDeleteMyRezzedObject(). This allows not having to devote kill commands or even scripts to handle culling of rezzed objects with or without the presence of their rezzer.