Frothingslosh,
You are right, if a system is truly redundant ,reliability is improved. I think what Gerald was referring to (and I agree with him) is that a lot of the systems sold for use in our jets are not redundant and add additional components that can cause a crash if they fail. For example if I add a regulator I have added one more component that will cause a crash if it fails. Reliability decreases.

An example of a redundant battery system is where two battery packs are on separate switches with separate wiring to the receiver. One battery/switch backs up the other. If one battery or switch fails the system will continue to operate off of the other. On the other hand if you use one of the systems that have one battery powering the receiver and another powering the servos you have just doubled the probability of a battery failure. If either battery fails you will crash.

A simple rule of reliability is that as you add more components reliability decreases because you increase the probability of a component failure, so KISS. One way to improve reliability is to add a truly redundant system or component such that if one component fails the back up takes over. Another way is with a failsafe design, like a switch that fails in the closed position rather than open.

From some of the postings I've read it is obvious that a lot of rc pilots do not understand what redundancy means, and a lot of the so called safety equipment on the market actually decreases reliability.

Joe