Your balances on Ripple are not real. They don't exist, they never existed in the first place and will never exist. Some people honor their printed Ripple balances, but for how long?
It doesn't have to be malicious by the gateway.
What if the gateway loses all the bitcoins through a natural disaster and a poor back up strategy?
What if the Department of Homeland Security seizes the gateway's stored bitcoins, like what happened earlier?The answer is.. nothing changes. You never owned anything of existence in the first place.
"We can win a major battle in the arms race and gain a new territory of freedom for several years. Governments are good at cutting off the heads of a centrally controlled networks like Napster, but pure P2P networks like Gnutella and Tor seem to be holding their own." - Satoshi Nakamoto
Napster was a centralized network controlled by one company. It was closed source. You had to trust files that they were legit.
Ripple is a centralized network controlled by one company. It is closed source. You have to trust gateways that they actually pays out.
Bitcoin is an decentralized network, controlled by every peer (that's you) who run Bitcoin and enforces the network rules. It's open source, and you don't have to trust anyone. A bitcoin, is a bitcoin that can't be seized without physical or malware intrusion - because it's enforced by every peer.
History repeats itself. Don't blindly follow Satoshi, but as someone who has created Bitcoin, you have to give their word a moment of thought.