I lot of people are being hacked after the free trade update. People are blaming Jagex, but I believe they had keyloggers or fell victim to phishing scams - the hackers/phishers waiting for free trade before taking action.
Make sure your account is secure! I've been sitting in Mod Mark's clan chat, and I've seen many an account come in saying they've been hacked. Or, the hacker themselves coming boasting that they've hacked an account. Be careful!