So the study about cellphones proved no interference to hospital equipments, who said it did in the 1st place?

Answer 1

The ignorant. Same idea, what they don't know won't hurt you. There aren't too many Engineers that work in a hospital since I last checked. I think someone in the Liability department or insurance company that are not engineers are not willing to take any unnecessary risks.

Answer 2

No one who had given the matter serious thought. I suppose that the reservations were more about disturbing people rather than equipment.