Greatly appreciate the warning. I had a misconception that Dropbox sync was securely built in to KeePassDroid (I haven't used KeePassDroid that much yet), from reading this Market user review: "Use this in conjunction with dropbox, works great!".
Lat thing I want is to bad-mouth an app I'm not familiar with - for all I know, the encryption on the locker that gets uploaded is more than just peachy.
Maybe a good idea to check the dev's website or drop them a line - like the old boy said, trust but verify.
And DropBox is supposed to be secure but I'd say it's one thing to entrust your normal files, another to entrust a container with critical passwords that can open up all sorts of things without being 100% sure that if DropBox were compromised, that stolen locker would still be safe.