Y shouldn't I use cellphone in hospital

Last time I went to a hospital (couple of years back) I was told to switch off my cell phone in some areas. At that time I thought that it was because that it would disturb the patients. Today after almost two years I came to know the correct reason behind this. You know what, I was stupid enough not to relate it with not using cellphones in the airplanes.
The thing is, the electromagnetic interference cause the electric equipments in the hospital to behave bizarrely. As one of the example on CNN was that a mechanical breathing(ventilator) machine went on/off on its own when a cell phone was brought near it. Now just imagine yourself hooked to that ventilator machine and breathing through it, and your sweet heart talking on a cell phone with her friend or somebody which may cause the ventilator to turn on/off, guess what your sweetheart would no more be sweet any more as you heart is in trouble now.
There are many other examples derived from tests conducted on this matter , I wrote the above stuff after reading an article on CNN (please refer to the "no cell phone zone " section) . All credit goes to the author of the article.
So please be considerate and obey the signs, as it can be injurious to somebody's health.