For those who aren’t aware, in the games industry the distributor has been in the role of adding DRM to games on the pretense that they are “protecting their interests and channels”. As the distributor, Google may feel empowered to make these sort of “protective” changes, and the one that would be most likely (in my estimation) would be wrapping the APK such that it played a pre-roll ad before your free game started.
I could be completely off base here but to my way of thinking it would be consistent with Google’s moves in the past.