Don't corporations insure themselves against these risks?
Reminds me of when I balked at my home insurance company trying to bump my rates 20% one year- they said it was because of the 2011 Japan earthquake (I'm in Canada). I laughed and walked right out.
From my experience, it's also plausible that some poor schlep in the accounting department was tasked with looking into self insuring, and created a not-very-robust risk model. At AOL's size one would hope an actuary was involved, but that may not be the case.
As well, even if am actuary was involved, that doesn't stop upper management getting peeved when payouts are towards the upper bound of the model, as all they likely saw was the potential cost savings of the lower bound of the model, not the full risk.