Sync, in general, is a very complex topic. There are past examples, such as just trying to sync contacts across different platforms where no definitive solution

Sync, in general, is a very complex topic. There are past examples, such as just trying to sync contacts across different platforms where no definitive solution emerged. One fundamental challenge is that you can’t assume all endpoints behave fairly or consistently, so error propagation becomes a core issue to address. Returning to the contacts example, Google Contacts attempts to mitigate error propagation by introducing a review stage, where users can decide how to handle duplicates (e.g., merge contacts that contain different information). In the broader context of sync, this highlights the need for policies to handle situations where syncing is simply not possible beyond all the smart logic we may implement.