Cell Phones in the Classroom.

Norms re. cell use are shifting, as evidenced by this article in the NYT (link requires free registration):

ANSING, Mich. - Sitting in his second-period computer class at Eastern High School, Gray Taylor, 15, felt his cellphone vibrate. To avoid being caught by the teacher, he answered quietly - and discovered an unexpected caller.

"Why are you answering the phone in class?" Gray's mother asked. He whispered back, "You're the one who called me." His mother said she had intended to leave a question on Gray's voice mail.

As bariers against cell use lower, are there rhelms in which cell-ban barriers should remain high?