I think with good presence (being able to see what other users are doing) and an app that isn't used offline, conflicts are essentially not a problem. As long as whatever is resolving the conflicts resolves them in a way that doesn't break the app, e.g. making sure there aren't cycles in some multiplayer app with a tree datastructure. Sounds like Zero has the right idea here, I'll build something on it imminently to try it out.