Note that the sandbox at all levels except Full V may allow the deposition of spawned daughters on the drive. As noted in the review these files would be orphaned and if run directly would be back in the sandbox loop. Another issue with the Partially Limited setting is that various PUP's will be allowed to install themselves to some extent. This can be a pain when the parent PUP spawns multiple installation routines.
The use of the Full V level will contain all spawn and PUPs, deleting them from the (virtual) drive on sandbox flush or reboot.