Holy crow, I never thought of that specifically--But of course, it makes so much sense that they would. This is so sad!!! Everyone I know has a cellphone. My mother has two.
I can see clearly what the stress of doing something you know to be detrimental is doing. Where there is a split mind, there can be no unity of body. And many reluctant users are young people who feel they have no choice, since they lack the 200 or more up front to pay for a "land line".