Complex systems are hard to secure. It's a statement that gets made time and time again and it makes perfect sense. If you have a system where interactions between various components is complex and difficult to describe or monitor then you can be sure that the failure of components within that system will have consequences that are hard to foresee or appreciate. No surprise.
Security
ATM security is hard
Securing an ATM is hard. Consider this, you have a small compact (albeit strong and heavy) item stuffed with cash in a publicly accessible place. Unless you can sufficiently protect it, it's going to become a liability.
