Well, we have some connections with the community and we are discussing how to incorporate our buildings IDs in OSM. The other way around (OSM to national registry) seems more complicated for license reasons.

Last summer we tested the open approch by doing a "RNB Summer game". Basically, anyone could come on the map and send some error reporting, we had a score per player, per territory and a shared global score. The OSM community absolutely rolled ont the game :)