If you've ever had a doctor cancel an appointment at the last-minute, or sat in a waiting room for an hour before being seen, your first impulse might be to go home and post a negative review on a site like Angie's List, Yelp, or RateMDs. Some physicians are now asking patients to sign waivers that say they will not post negative comments on such Web sites because of concerns about the fairness of such reviews, says the Associated Press.

The American Medical Association has not taken a position on waivers, but AMA President Nancy Nielsen has said that Web sites where patients can rate their physicians "have many shortcomings." Comments posted by patients on Web sites "should be taken with a grain of salt and should certainly not be a patient's sole source of information when looking for a new physician," she said.

We're certain this news will raise ethical questions and draw strong opinions and from both doctors and patients, and we'd like to hear from you: Do you think it's ethical for a doctor to ask patients to sign such a waiver? Why or why not?