If this was possible, iCloud+CoreData would have worked, and Oracle/PostgreSQL/etc would be shipping transparent, ACID, horizontally scalable RDMS.
- DBResolutionRemote: The remote value will be chosen. This is the default behavior for all fields.
- DBResolutionLocal: The local value of the field will be chosen.
- DBResolutionMax: The greater of the two changes will be chosen.
- DBResolutionMin: The lesser of the two changes will be chosen.
- DBResolutionSum: Additions and subtractions to the value will be preserved and combined.
So with these limited conflict resolution options conflicts might occur but they can be resolved automatically. I am not saying this is good or bad but beside setting one of those resolution modes there is nothing else to do - except explaining to users what happened to their data in the case of a conflict that should have been resolved with a more sophisticated mechanism.
iCloud+Core Data on the other hand allows custom conflict resolution on the clients.
The new APIs in iOS 7 do, but then you lose all the value of "transparent distributed store" and it winds up being a pretty sizable hassle.