Those reserved 3 gigs has to be in the "game data", where else would it be?
Someone test this please, I want those precious gigs back. (I'm not around the PS3)
Deleted Home from the PlayStation Network menu. It was around 3080 MB.
Deleted Home files from Game Data Utility menu. 15 KB.
Deleted Home Settings File from Saved Data Utility. 87 KB.