Grizzeld,
finally some new and extremely valid point.
I was involved in developing a non certified database for
non certified GPS/FMS system for Poland.
I can assure you, that what we achieved as amateurs was way
above the database provided by the certified Garmin units.
The other problem is, that in case of some ex soviet military airbases
the data were biased on purpose. If somebody was not aware of it
and didn't take care to, at least, compare them with the satellite images,
then the result could have been disastrous.
Once having aboard a modern FMS and using it in most cases, one
develops a treacherous, blind confidence in it and stops thinking...
Being used to fly according to your nice "glass-cockpit" screens, you sometimes
forget to look out through the windscreen...