I suggest adding an option to the Game Manager that, when active, automatically deletes all data about players who have been inactive for a long time (e.g. three months, configurable by the game developer). It would be equivalent to calling DeleteMasterPlayer for all those players, but preferably wouldn't send an email for every player.
The use case is compliance with GDPR, which requires that personal data is retained only as long as necessary. See this thread for reference.