While I realize I work at a VET hospital not a human hospital, and I'm having to assume that human hosptials run into at least some similar hassles that we did at work. I'm guessing that some of the no cell phone rules may have to do with doctors being able to discuss treatment etc. with the patients and cell phone conversations interfering.
The reason I say this is...
Until a few years ago our vet hospital allowed cell phones inside. We had the usual loud talkers, people who just HAD to answer that call from the kid at home wondering what was for dinner right when the dr. was discussing what to be expected during an upcoming major surgery, walki talki mode set on LOUD so you could clearly hear both ends of the conversation through closed doors, annoying and LOUD ring tones (all of which I might mention tend to frighten timid animals which puts us at higher risk of getting bit).
The FINAL straw was a few years ago. This actually happened! We had a client come in already talking on his cell phone. He sat down in the lobby with his large dog. Never said a word to us and would NOT answer us when we asked his name. We had to match up the dogs discription with the files to figure out who he even was, and check with the appointment book just to find out why he was there! He did respond by getting up when we called the dog's name.
So we put him in a room (not so much as a break in the cell phone convo), and we could hear him in there just yakking away. It wasn't an important call from the end we could hear. At some point while he was in there we heard him say 'bye' and it got quiet. Yay, the guy hung up finally! So much for our elation, nope, do you know what he did next? He dialed up someone else and started up the yaking on the cell phone again. Once more didn't appear to be an important discussion, more like social calls.
So when his turn came the dr. walked in the room, the guy on the phone didn't even look up to acknowledge the dr!! He wouldn't respond to any questions asking about the dog's health since his last visit. So the dr. just did his examination, all while the guy is yakking away. The dog appeared healthy and happy, was due for a vaccination as I recall, and we went ahead and did that and told the owner unless he had questions that he was done. The guy didn't even so much as NOD and walked to the check out with the dog, yaking on his cell phone the ENTIRE time!!
From what our receptionist said, the man talked the ENTIRE time he was checked out, still never responded to questions or acknowledged ANYONE. Just flopped his credit card on the counter, gathered his reciept and left with the dog, STILL yakking on the phone!!!
Later that day the boss put up signs all over the hospital saying NO CELL PHONES INSIDE THE BUILDING!
I'm guessing that if human dr's have had similar things happen, or had someone else in the room yakking on the cell phone while they are trying to discuss a serious medical condition to a patient, that they'd be a little 'down' on cell phones also.
It's not the phones themselves that are the problem, it's the people that use them, and HOW they use them.