Most surgical procedures fall under "global billing". Any care customarily related to the procedure is covered under one bill/one payment. The time covered by the global time period varies with the procedure, most are on the order of 6 weeks to 3 months. You can bill for treatment of complications but you don't get payed real well if you did the original surgery. And Medicare billing at hospitals is based on DRG'd(diagnosis related groups), pnuemonia gets paid a certain amount of money, no matter how long they are in the hospital. So it isn't all that big of jump to offer a warranty, especially if they can negotiate more money for the guarantee.
I don't have a written checklist, but I essentially run through one in my head with each operation. I think most obsessive-complusive people do that, and most surgeons are a bit O-C.
Barb(poor general surgeon because I try not to have complications, so I don't get to bill for more procedures.)
