If you're worried about the kids messing with your music:
1) Teach them not too.
2) Setup separate accounts with only read permissions on your music. This is much better than password protection in MediaMonkey as it prevents them from messing with the files outside of MediaMonkey and prevents any malware they get their hands on from messing with the files. I use the same, only one user account on one PC has write permissions as that's used to edit the songs, everybody else has only read permission thus protecting my music. For me it's just malware protection. You also have to consider that having multiple libraries wouldn't prevent the kids from scanning in your music in their library and messing with the tags. (One Add/Rescan Tracks in your library and the tags are messed up in your library too).
If you're worried about the kids messing with their music:
1) A filter is enough as you want to hide their music.
Also Onkel_enno's database switcher works well and would probably work in a similar manner than a build in method. The only thing that you need to do is to start MediaMonkey with the database switcher.
All this doesn't mean that I don't support the idea of multiple libraries, but I do understand given the available options that this is not necessarily as high on the priority list of the developers. I also assume that it might be hard to implement an in program database switch.


