Someone needs to check to see if this will actually let you spawn more objects than you're allowed to. If no one does, I'll try the next time I get on.
It won't work if it isn't saved. Say you saved your map earlier, then place 20 objects, then they get deleted, and you didn't save since before you placed to 20 objects. Now if the hosts leaves only the pre-saved objects will appear, not the non-saved ones.