I'm honetly not sure how blockchain.info doesn't ahve your private key. They need it to do anything.
I think they store, on there servers, some peice of data, that when combined with your password, turns into the
private key
That's my point really, as far as I know they have all the information needed to empty my wallet.
I do not know them well enough, and I guess the same could be said about any bank in the world.
I guess what I am trying to say is, not wallet is truly 100% secure, (but as I said, the same could be said about any currency, look at Greece or Cyprus for example).
FFMG