[erroneousfunk]

Insurance companies and hospitals "accidentally" bill you for the wrong thing all the time, even for the little stuff.

I went to the ER for a broken hand a couple years ago, got a $450 bill in the mail when I should have just had a co-pay. Called the hospital, they said I had to pay. Called my insurance, insurance company said I didn't have to pay. Got in a three way call with the insurance company and the hospital... The billing specialist at the hospital literally said "Sorry, that's a known billing error!"

I'm generally not a conspiracy theorist, but I've never heard of a medical billing error that was in favor of the patient... If you see something alarmingly high or out of whack (especially if you've done your due diligence, read and understood your policy, and researched covered hospitals) you'd be silly not to fight it.