Fran, you are correct in saying operator error is usually the culprit in DB problems. But, especially with a newbie (that still hasn't quite grasped all the concepts), operator error is a high possibility... And, IMO, the DB needs to be re-written to make it more robust, more immune from operator error.
There are many things the OS does that make poor sense... One of my favorite peeves is that Linked SMFs do NOT call the linked SMF into the Finder when calling up the UPG. Unless you are VERY aware of this (the manual sure doesn't warn you!) you can start doing DB functions to it, and in fact you are working on the last file that WAS in the Finder...
Another disadvantage to this is that you call up an SMF Linked to a UPG on the gig, and do a little Makeup Tool work to it (the best place to accurately dial in your SMFs, IMO), come the time to save your edits (remember, you are on the gig, so this needs to be quick and easy!) and there is NO filename in the Finder. You can't simply press 'save' and 'overwrite' and be done, you have to KNOW the exact name of the file, type it laboriously in (VERY slow here) and THEN do the save/overwrite.
This takes FAR too long to be practical. It is a shame, because tweaking on the gig is otherwise SO easy with the Makeup Tools, you really want to do it all the time. But the lack of integration between Linked SMFs and the Finder make this more difficult than it should be...
There is a litany of weird problems associated with the DB at roland-arranger.com and it's predecessor site, obviously, it seems operator error is a fairly common thing! The manual has little in the way of cautionary warnings about what NOT to do, and once corrupted, the DB is very difficult to recover. All of this leads me to not trust it, despite being fairly well up on the G70 (!)
The combination of Richard's Session Manager software, and using multiple UPSs to organize UPGs just is, IMO, a more bulletproof system. Stephen could simply make up a UPS that contains the registrations for his wedding playlist, and load that as a virtual 'gig disk' and avoid the floppies altogether (and the DB!).
Perhaps, once he is more up to speed on the G70, he can try using the indexes, but I'm not sure I would recommend it to a relative newcomer, especially one coming from Yamaha, and not a prior Roland...
_________________________
An arranger is just a tool. What matters is what you build with it..!