That may not be a good idea though. Considering someone can have their email compromised an attacker would have access to their wallet backup.
IMHO, keeping funds on blockchain.info is not a good idea to begin with.
I should have mentioned it and I agree that *if* you use such a wallet to use a massive password and 2FA everything you can, including your email. Regardless what backup option you use. Also bug blockchain.info to allow you to paste your public GPG key, so all communication would be encrypted.
Edit: Also make it a habit to change your massive password every so often.