Another thought

On pg 132, Baron says "I have yet to hear of Americans using their mobiles for beeping as a thrift measure." (Beeping is calling someone, letting the phone ring once, and hanging up in order to avoid using minutes or paying extra). I have done this before - not because I was out of minutes, but because my friend was out of minutes and texts. I was planning to meet him at his dorm on a football weekend, so he had to let me into the building. He told me ahead of time to call him and hang up right away so that he would know I was there (at this point ND had stopped providing landlines in rooms).