We have big issues with duplicated models in iTwin design review. This is probably according to Bentley because the same file for some reason has been synced to the imodel before in a different connection. So if thats the case then there needs to be a warning and the sync stops if the file is already synced in another connection or if the file contains references that are already synced in another connection. It should not be possible to create duplicated models.
Great idea!