After reading this thread I have two questions in my mind:
1. What if the robber hacks and takes off all fund from ATM?
2. Why ATM's when they are so risky?
1. If the robber is too good at hacking, Maybe he can get those bitcoin address in the history of the ATM but he can never get those private keys and get users account. The robbed money is never related to users fund so its from the operators account.
2. Everything is risky and its just an isolated case. Even fiat ATMs and banks are robbed. So its not that big deal to worry.