How to prevent android system from creating folders on internal storage
The way to prevent creation of new files/folders inside a particular folder is to use the chattr +i command. Using "+i" makes it immutable, preventing changes by anyone, including su, until you do -i .

so doing: chattr +i /data/app

and then running: mkdir /data/app/blah will fail
but mkdir /data/app/com.android.vending-1/blah will work fine