If you bother check Bitcoin Technical Support, there are few cases where such case happened. But there are many reason why wallet could be recovered or not, such as how intact is the wallet and how much the owner remember the password.
They follow BIP standard and their software is open source, so it's less likely you'll lose access to your Ballet wallet. But you could always write down hint of your password, save their documentation and download their software if you worry that much.
P.S. If you have more concern about Ballet wallet or preserving your wallet, please create new thread instead.