said by elray:[...]
But seriously, how does a redundant fiber loop get "accidently" whacked on both ends?
Depends on the technology.
One I'm familiar with has a ring structure, it's designed so that with one cut in the ring everyone can still talk to each other. But if you had a second cut, you'd get a partition, with the nodes on each segment being able to talk to each other but not to nodes on the other segment.
The dual fibers would be additional redundancy on top of this, so that if a repeater or whatever fails, the other fiber can carry all the load.
However all of the above is merely semi-informed speculation, without knowing the architecture I can't go any further, I can just say the above posited architecture would be a good one and would very seldom fail outright.
And of course as others have noted Alaska Airlines perhaps should have not been so dependent on a single vendor, but that's a $$$ vs. risk judgement and one they still might be ahead on.