That's one step away from fractional reserve Bitcoin: someone deposits 1 Bitcoin, someone else borrows 0.95 Bitcoin and deposits it again, after which someone else borrows 0.9 Bitcoin and this keeps repeating until the bank owns everything because of interest.
I don't believe there will be any fractional reserve Bitcoin. If you can not double spend bitcoin, you can not have a factional reserve!... You can not lend out 1,000btc, just because you got 100BTC in your wallet. That's the beauty of Bitcoin! My Node will tell me if you got the real stuff, or not!