[caesarshift]

Yes, in my experience, using dropbox, you end up with two versions of the keypass file (one listed as a conflict). I've been using this setup for ~10 yrs, and it has only happened 2 or 3 times, but as I'm the primary user, I would expect this to happen more often with a family sharing the same file. If things are working correctly, the keepass lock file created when opening a db is synced via dropbox, so any second attempt at opening the file on another system results in a warning to open it as readonly.

[WorldMaker]

Because Keepass uses GUIDs internally for most operations, merging the conflict files is usually trivial (use the Sync options in the Keepass UI of your choice from your main file, then you can safely delete the file marked as conflicting). (The GUIDs thing has also meant that I've had some success merging unrelated files too over the years, though that is probably less advisable.)