[giaour]

If every tap generates a “[TIMESTAMP] $USER is on page X in book Y” event, then the there is no difference between recording tap events and syncing progress state in terms of what the client is reporting.

The difference lies entirely in what WhisperSync is storing, which you can neither know nor control.

[Godel_unicode]

You might be surprised to learn that you can both know and control, using the mitm approach from the below thread about KSP:

https://www.mobileread.com/forums/showthread.php?t=174403