Originally Posted by Helena Handbaskets

I'm pretty sure (though not 100%) this is correct:

In the U.S. there are what is known as "Good Samaritan" laws that protect anyone, whether medical professionals or not, from liability for services offered in emergency situations such as a heart attack on a flight. Any medical professional would certainly be familiar with the existence of these laws, so I doubt that fears of being sued would prevent a medical professional from self-identifying in this situation.