1963, my bride-to-be was driving our 55 BelAire on a steep downhill toward a stop sign at a busy 4-lane. NO BRAKES. Fortunately she was able to thread into and through the 4-lane traffic without incident. Somehow one tailpipe had shifted and was rubbing on the brake line and had actually worn it through so there was no pressure. Granted, this was on 17 year old me for a poor installation of the tailpipes. But stuff happens. It made me a believer of the dual brake systems when they became generally available. I have upgraded both of my toys to dual systems even though they came stock with single master cylinder systems. I don't see how they are less safe than with the original systems. My 2 cents.
Mark