Library check before clear and rescan?

Hi

I use the Rescan Music Libray plugin to rescan nightly and pick up the previous day's changes.
But next day I sometimes see the dreaded "Empty" on browsing My Music and discover that my library has been cleared due to an issue with my server share not being available at that rescan time. :-(

The issue could be that the Windows server was unavailable for some reason or that the share mount from LMS on PCP has failed and not recovered (this seems be a recurring frustrating issue with Samba). The impact is that I have to wait for a couple of hours while the library is rescanned. :-(

So I guess one option is to change the scan type to be "Look for new and changed media files" but I've not been able to find a description of exactly what "new and changed media" means. However I have seen that this scan method often has issues with (not) scanning changed tags which is quite often true.

Otherwise it'd be really handy if the "Clear and rescan" could do some form of elementary check to see that the library is accessible before it deletes everything.
Or is there another way or recovering the previous library database?