If we all bet on Murphy, (as in Murphy's law, as String mentioned), then none of us would dive, because a double redundancy failure can happen.
At some point, we accept that somethings have an acceptable level of risk, and proceed.
I also skydive, people always ask me what if my parachute doesn't open?
I have a reserve.
And if that doesn't open?
I die.
A double malfunction is rare. Sure, it can happen, but it's an acceptable level of risk for everyone who skydives.
Me and my Spare Air are walking out the door to catch some lobsters, you guys can keep diving the net. I'm done with this thread.