Black, if one backs that up automatically and will still use synchronising, it can happen some backups would be overwritten the same way as here in question.
Just to be clear.
Indeed, if I understand you correctly. However, the backup file itself would still preserve the data that was current at it's creation/update date, so it could still be re-restored. As such, a backup represents only a source for getting a particular system's data/settings safely 'back home' to the date of the backup file. But, of course, it would require the user to make sure 'sync' was shut off for that system to prevent the restored data from being over-written by a faulty sync record, until the sync record base could be correctly updated from the restored system and until one could make sure the entire sync system was operating correctly.
My comment was intended only to suggest a data backup mechanism always be kept in place and reasonably current for 'getting home', and wasn't intended as an analysis for what went wrong (or may remain wrong) with the sync process itself. The harsh life-reality is that something will almost always eventually go wrong with syncing systems, and it is wise to never consider sync or its other netted computers as a kind of backup scheme in case data gets lost on one of the netted systems. Syncing, by its inherent nature, can automatically propagate an individual system's data loss to every one of the netted systems, if either the user or the sync system makes a miscue.