My stand is that in case of Bitcoin the reserve rate will be 100% in long run (and would be with every currency unless government creates central banks and bailouts insolvent institutions). Only 100% reserve would work for Bitcoin banks because nobody can create central bank for Bitcoins.
Sure they can after all FRB existed when gold and silver were the mediums of exchange with and without central banks, and central banks certainly couldn't make gold or silver out of thin air. The central banks just need to keep a reserve of whatever medium of exchange they use in reserve if they're using a non-fiat system. Obviously unlike gold and silver transferring and holding bitcoins is not much of a burden so it doesn't make a whole of sense, but just like there's a chance of a 99% reserve bank system failing so is the possiblity of a bitcoin FRB system.