I just had a eurieka moment... (For me, it's VERY rare...) :-/
Maybe, as a security feature, you could have a 'lock out feature' which would prevent anyone (including you) from accessing the app if an incorrect password is entered 5 times continuously... The user would then have to delete the app, re-install it and know the dropbox password (which is sent to the users email address via an encrypted file from the app itself) and the user could then set up the app again!
Thank You so much for taking the time to read this 'unearthly' post!!!!!
Jacob Hill ;-)