So I'm ~~only~~ an EMT, but I want to weigh in here to this conversation.

I had to tell a patient with severe pneumonia (and the patient's family) that you don't get sick (i.e. catch a cold) by leaving your skin exposed. The family was vehemently debating me on the fact claiming that I had no idea what I was talking about because I'm not a doctor.

Attempting to explain to them the necessity for a foreign body to enter your system was the most preposterous thing to them.

Edit: I just want to say to everyone who flooded my inbox with wonderful sentiments regarding the work of EMTs and paramedics. That appreciation makes dealing with the seemingly inexorable chorus of professionals telling us (me) otherwise much easier.