Why not just market games that require cloud processing to play as online-only? It's a bit much for the entire system to have to take on this always-online requirement for games that may not have a multiplayer or large universe aspect.
> attr_accessible suffers from context blindness: you’re frequently going to have an end user UI and an admin UI. You want admins to have access to more fields.
This is exactly why edge Rails is moving towards strong_parameters, where these are enforced by the controller rather than the model.