A few months ago I read an article in some major newspaper (NYT?) re a company that trains people to audit medical bills for errors. They certify their trainees, and set them up to start a franchise-type business which makes its money by getting a cut of the incorrect excess charges found. Seems most medical bills are loaded with invalid charges. I believe insurance companies are the primary clients for this business. Google around and I'm sure you can find it.
I'll definitely have to look into that - that's something I could do.