Also as an American, my experience was that the majority of high school students didn't care about the rules on phones. I attended high school when Motorola Razr flip phones were the hot new technology, and kids used them in class all time. People learned how to do T9 texts without looking so they could slip their hand into a backpack or pocket during class. There were even ringtones high pitched enough that adults typically didn't hear them. All of this under the threat of phones being confiscated if caught.

I'm not defending the use of cell phones in class. But there have to be more effective ways to reduce their use among students rather than simply banning them.