On the http://www.creationkit.com/Persistence_(Papyrus) it's stated that any reference that's attached to a script property will be permanently persistent. That is, it will never leave memory. Does this mean that it will be loaded into memory when the game is loaded and then it will stay forever? That's what it sounded like, but I find that hard to believe. That would mean basically every possible object in the game will be loaded into memory and never unloaded from memory because nearly every object in the game is connected to at least one script property somewhere.
Instead, does it mean that any property reference will be loaded into memory when that script is loaded (Such as entering a cell containing the script), and from that point until the game is closed it will remain in memory? That would make much more sense.