I thought very briefly about getting it, but realized it would be far from ethical for me. As my wife is a hospital employee, the hospital writes off all co-pays, etc. So, if I went to the ER for a runny nose, I'd make a profit after Aflac.
That said, I don't think it's really worth it. The idea behind insurance is to pool your money to insure against risks. Do you really need to insure against ending up with a couple hundred dollars in bills? Or, even 2 thousand in miscellaneous hospital fees that aren't covered by insurance (probably a worst case scenario.) Hospitals are generally willing to agree to payment arrangements, allowing people to pay what they can afford over a length of time. So, worst case - you pay off your bills, but afterwards, and generally with no interest tacked on.
Aflac: you get to pay those bills right away. Aflac sure spends a lot of money on television commercials, don't they? They sure pay an aweful lot of salespeople, don't they? Where does that money come from? i.e. they're making a hefty profit off people willing to take out an insurance policy that really isn't as likely as people perceive to pay off for them.