Poppycock.

There are two ways to fix this. One is to not permit dynamic code loading or app installs off the Play Store. This is Apple territory and pisses people the hell off. The other is to not have any world writable filesystem at all. I guess you could do this, but this messes with features surrounding music and pictures that you do want to share between apps.

Epic literally could have used the private filesystem that is right there just for the purpose of having files that are protected from other apps.