The problem here is that most of the replies (not yours necessarily, you were just the closest one to "quote") assume that school personnel have nothing better to do with their time then go around calling doctors (who may or may not divulge information anyway) being nosy trying to find out when the last time was your child had a sore throat. (And again, who cares???)
99% of school personnel a. don't care unless an emergency arises, b. respect your privacy enough to not go nosing about, and c. have enough crap to deal with on a daily basis that your quite-healthy child's health records are WAY low down on their priority list.
I think we can all agree that our nation faces an epidemic of un-involved parents (obviously not on the Dis, we are all perfect, with perfect children, remember

) and I think that we can also all understand that school may not be getting the information needed to care for students in an emergency. And yes, in a legal situation, schools DO have to cover their butts.
Sorry, but if little Johnny goes into shock over a food allergy that was not reported to the lunch ladies because his teacher didn't have that information, and it could have been prevented by a quick call to the pediatrician the first time someone noticed something amiss, then to me that makes it worthwhile. After all, if the nurse calls little Johnny's doctor and asks 'I noticed that when Johnny drank milk yesterday, he had trouble breathing in P.E afterwards. Can you tell me if there is a dairy allergy I should be watching out for?" I find it fairly unlikely that the doctor will launch into a full-blown conversation with her about little Johnny's genitalia. Let's give our medical professionals a little respect...