I found a jQuery plugin some time back called "Dirty Forms" that helps prevent users from navigating away from a page when the form has been altered, without a save.
There is a Drupal project that is out dated (and yes there is a Drupal 7 patch that doesn't seem to work very well).
In other words, when a user types in the text area that TinyMCE generates, the Dirty Forms plugin doesn't see that change, and doesn't properly flag the form as edited, and the user can march right off the page without a warning.
We've also experimented with the Node Edit Protection module, but again, not very widely maintained or used, and it doesn't seem to work as well as Dirty Forms cross browser.
I'm wondering if anyone has any advice about this issue, possibly if you have implemented Dirty Forms yourself, or have any thoughts on monitoring the contents of the WYSIWYG editor inside of the iFrame.
Love WYSIWYG, just trying to add some user experience enhancement to help users not lose their content.